The study is designed to examine the predictive power of Saudi-admission criteria for student performance in an introductory biology course. It focuses on the second semester at King Saud bin Abdulaziz University for Health Sciences. The study addresses whether the General Aptitude test (GAT), the Scholastic Achievement Admission Test (SAAT), and the students' English proficiency, taken together can accurately predict student performance in the biology course. Their English proficiency was measured by using the average grade in the intensive English courses taken in the first semester, in addition to the average grade in the reading and communication proficiency tests. The research involved the results of 250 male students in the admission criteria and biology-course grades. Simple linear and multivariate regression models are used to determine the predictive variance of each admission criterion for student success in the biology course. The results demonstrate that the admission criteria are significant predictors, but with a variance of 26.6%. The results also show that individually, GAT and SAAT are the poorest predictors, whereas the reading and communication proficiency tests were the best. The findings reveal that the predictive power of these admission criteria as a combined model is low. Additionally, more investigation is necessary to ascertain whether these criteria are also low predictors in other subjects and in overall college learning.