MLH Fellowship vs Regeneron ISEF 2026

Comparing two highly competitive STEM opportunities. MLH Fellowship is a internship while Regeneron ISEF 2026 is a competition.

MLH Fellowship Regeneron ISEF 2026
Prestige Tier Tier 2 — Highly Competitive Tier 1 — Elite
Type Internship Competition
Organization Major League Hacking (MLH) Regeneron
Acceptance Rate Not publicly disclosed; competitive program but exact rate unknown Roughly 1,700 finalists are selected from 365 affiliated fairs worldwide. Getting to ISEF requires first winning regionally, which itself is competitive. Estimated <1% of all science fair participants globally reach ISEF. At the ISEF itself, approximately 600 of the 1,700 finalists (~35%) receive some award.
Applicants Not publicly disclosed; appears to have multiple cohorts annually Millions of students compete in science fairs globally each year; approximately 1,700–1,800 reach ISEF as finalists
Deadline Rolling
Cost to Apply Free Free
US Only No / International No / International
Grades College students and above (program appears designed primarily for undergraduates; high school eligibility unclear) Grades 9–12 (high school students only; middle schoolers compete in the separate Junior Innovators Challenge)
College Impact Highly valued in college admissions and recruiting. Shows: (1) Real-world experience with production-grade code, (2) Demonstrated commitment to open-source/collaborative development, (3) Recognition b... ISEF finalist status is one of the most powerful extracurricular credentials in college admissions. Being named an ISEF finalist (simply qualifying) is Tier 1 on most admissions frameworks. Grand Awar...