Introduction:All medical schools in Saudi Arabia have English as the primary official medium of instruction. Most of the high school education, however, is delivered in Arabic and hence the transition to an English based learning environment tends to be difficult for some students. Our study aims to correlate English language proficiency with academic performance among medical students in their preparatory year.Methods:A cross-sectional study design was used. Test scores of 103 preparatory year students (54 female and 49 male) were analyzed after the students completed an English language course and medical introductory course in their preparatory year. The total score obtained in the English course assessment was compared to each component of the medical content assessment.Results:A significantly positive correlation (Spearman's Rho, at 0.01 levels) was seen between the scores of the English exam and the written exam (P <0.001) and the oral exam (P = −0.003) parts respectively of the medical examination. Significant correlation with the English exam score was not obtained for the other components of the medical assessment, namely; student assignments, presentations and portfolios.Conclusion:English language proficiency is an important factor in determining academic proficiency of medical students in our college at the preparatory year level.