How Hard is it to get into Cal Poly SLO? The 10 Most Selective Majors (2026)

Cal Poly San Luis Obispo, known for its hands-on "Learn by Doing" approach, has become one of the most competitive public universities in California, with certain majors experiencing particularly high demand.

Over the past two decades, Cal Poly SLO has seen a dramatic rise in both applications and selectivity. In 2004, the university received around 25,000 applications with an acceptance rate near 50%. By the 2025 application year, applications had surged to almost 82,000, and the overall acceptance rate had plummeted as the number of admitted students did not grow over the same time period.

This trend is especially evident in popular technology programs, where highly qualified students are getting outright rejected. The increasing selectivity reflects Cal Poly SLO’s growing reputation and popularity among students in California. In fact, as a college counselor, I often get questions regarding selectivity at SLO: Which major and alternate major should I pick? Which majors at the most impacted at SLO?

How hard is it to get into Cal Poly SLO?

Is Engineering super selective still now that CS isn't so popular?

In case you haven't picked up by the questions I'm asked, a distinctive aspect of Cal Poly SLO’s admissions process is that students are admitted on a major-by-major basis, requiring applicants to be committed to a specific course of study. This can add some pressure for undecided applicants, as they need to determine their intended major before applying.

Fortunately, Cal Poly SLO, as a California public university, is transparent with its admissions data. In this blog post, we will examine the ten most selective majors based on publicly available data from the most recent applicant pool in Fall 2025. Make sure to check out the entire list, as you’ll likely be surprised by the most selective major they offer!

Methodology

Before we dive into the majors, we just need to clarify the process we used to identify the ten most selective majors at Cal Poly SLO. Using data from Cal Poly SLO’s Institutional Research website, we focused on the following criteria:

1. Number of First-Year Applicants

2. Number of Seats Available for Freshmen

3. Applicants-to-Seats Ratio: We calculate this ratio by dividing the number of applicants by the number of available seats, providing insight into the competitiveness of each major.

4. Yield Rate: This metric, provided by Cal Poly SLO, indicates the percentage of admitted students who choose to enroll.

5. Estimated Acceptance Rate: Using the yield rate, we used an internal calculation estimate the acceptance rate for each major, as exact acceptance rates for individual majors are not published.

Without further ado, here's the list of the 10 most selective majors at Cal Poly SLO -- 2026 Edition!

10. Microbiology – 4.60% Applicants-to-Seats Ratio

School: College of Science and Mathematics

Yield Rate: 15.00%

Estimated Acceptance Rate: 30.65%

New to the list this year, Microbiology prepares students for careers in healthcare, public health, biotechnology, and lab research. With 522 applicants for just 24 seats, it’s one of the smallest programs in the College of Science and Mathematics, and that small size keeps it highly selective. Its numbers barely changed from our last update, but it moved into the top ten as several engineering and business majors dropped out.

9. Marine Sciences – 4.41% Applicants-to-Seats Ratio

School: College of Science and Mathematics

Yield Rate: 15.00%

Estimated Acceptance Rate: 29.38%

Marine Sciences, part of the College of Science and Mathematics, is ideal for students passionate about environmental and oceanographic research. The program drew 590 applicants for only 26 seats. That’s down from 746 applicants in our last update, which moved Marine Sciences from #4 to #9, though it remains one of the most competitive majors at Cal Poly.

8. Mechanical Engineering – 4.36% Applicants-to-Seats Ratio

School: College of Engineering

Yield Rate: 26.70%

Estimated Acceptance Rate: 16.33%

Mechanical Engineering, a versatile major in the College of Engineering, spans industries from automotive to aerospace. It’s also the largest major in the College of Engineering, and demand keeps growing: applications rose by nearly 1,000 since our last update, to 5,437 applicants for 237 seats. That growth moved Mechanical Engineering up a spot.

7. Political Science – 4.29% Applicants-to-Seats Ratio

School: College of Liberal Arts

Yield Rate: 20.40% Estimated Acceptance Rate: 21.03%

PoliSci offers students a deep dive into political systems, public policy, and international relations. Up one spot from #8, it drew 2,214 applicants for 95 seats this cycle, compared to 1,837 applicants for 86 seats in our last update. Known for fostering critical thinking and practical experience, the Political Science curriculum prepares students for careers in law, government, public administration, and advocacy.

6. Biochemistry – 4.24% Applicants-to-Seats Ratio

School: College of Science and Mathematics

Yield Rate: 15.00%

Estimated Acceptance Rate: 28.27%

The Biochemistry major, also within the College of Science and Mathematics, provides a foundation for careers in healthcare, research, and biotechnology. Applications rose from 1,611 to 1,745 for 74 seats, moving Biochemistry up from #7 to #6 and making it an even more competitive choice among prospective students.

5. Aerospace Engineering – 3.81% Applicants-to-Seats Ratio

School: College of Engineering

Yield Rate: 26.70%

Estimated Acceptance Rate: 14.28%

Aerospace Engineering is one of Cal Poly’s flagship programs within the College of Engineering, with career prospects in aviation, space exploration, and defense. This major saw 2,360 applications for just 90 seats, reflecting its high demand among students who want to work on airplanes and rocketships. Its numbers held steady since our last update, but it moved up from #6 to #5 as other majors became less competitive.

4. Public Health – 3.52% Applicants-to-Seats Ratio

School: College of Science and Mathematics Yield Rate: 15.00% Estimated Acceptance Rate: 23.50%

Public Health is one of the biggest newcomers on our list. Applications jumped about 57% since our last update, from 1,118 to 1,759, with no change to its 62 seats. The major appeals to students interested in disease prevention, health policy, and community wellness, with pathways into healthcare administration, epidemiology, and graduate programs in medicine or public health.

3. Kinesiology – 3.35% Applicants-to-Seats Ratio

School: College of Science and Mathematics

Yield Rate: 15.00%

Estimated Acceptance Rate: 22.34%

Also new to our list, Kinesiology is the study of human movement and a popular launchpad for students headed toward physical therapy, occupational therapy, sports medicine, and other health professions. Applications rose from 2,056 to 2,328 for the same 78 seats, making it one of the most competitive pre-health options at Cal Poly.

2. Biological Sciences – 2.93% Applicants-to-Seats Ratio

School: College of Science and Mathematics

Yield Rate: 15.00%

Estimated Acceptance Rate: 19.53%

Housed within the College of Science and Mathematics, Biological Sciences appeals to students pursuing fields in medicine, ecology, and research. It made one of the biggest jumps on our list, climbing from #5 to #2. Applications grew from 4,787 to 5,358 while seats dipped slightly from 159 to 157, making it now the most selective STEM major at the university.

1. Psychology – 2.46% Applicants-to-Seats Ratio

School: College of Liberal Arts

Yield Rate: 20.40%

Estimated Acceptance Rate: 12.07%

Psychology holds on to the top spot for the second update in a row. It’s a popular choice at colleges throughout the US, since it offers pathways into fields like counseling, research, and clinical psychology. Cal Poly added seats (from 73 to 84), and applications dipped slightly (from 3,657 to 3,411), but with 3,411 applicants competing for those 84 seats, Psychology remains the most selective program at Cal Poly. Despite its popularity, it’s still one of the school’s smaller majors.

What's Changed?

This year’s data looks quite different from our last update, and the biggest story is computer science. Applications to Computer Science fell from 6,304 to 2,530 (a 60% drop!), dropping the formerly #2 major off our list entirely. Software Engineering (previously #3) followed the same pattern, with applications falling from 758 to 319 even as seats increased from 25 to 39. Biomedical Engineering and Economics also fell out of the top ten. Health and life sciences took their place: Public Health, Kinesiology, and Microbiology are all new to the list, and six of the ten most selective majors now sit in the College of Science and Mathematics. This is clearly a reflection of the boom in AI moving a shift of student interest to pre-health instead of tech.

Conclusion Where there any surprises here? Let us know in the comments below! Navigating the competitive admissions landscape at can feel overwhelming, especially universities have such different policies of their admissions processes. However, with careful planning and support, you can make informed choices about the right major and increase your chances of finding that best fit college. At Thinque Prep, our college counseling team is here to guide you through every step, from selecting a major that aligns with your strengths and interests to crafting a strong application. If you have questions about Cal Poly SLO admissions or need personalized college counseling, don’t hesitate to contact us. Let us help you take the next steps toward your educational goals with confidence and clarity.

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About the Author

Joey Lin, also known as The Perfect Score Tutor, has over 15 years of experience in test preparation and higher education. Passionate about empowering students to achieve their academic potential and find their best-fit colleges, Joey delivers personalized guidance grounded in expertise.

In an ever-changing admissions landscape often clouded by misinformation and hearsay, Joey strives to empower his mentees by providing data-based, fact-driven insights. His expertise is rooted in his experience working with a variety of highly selective colleges admissions offices across the country and his active involvement in professional organizations such as IECA, NACAC, NTPA, and WACAC.