Crotin, RL, Forsythe, CM, Karakolis, T, and Bhan, S. Physical size associations to offensive performance among Major League leaders. J Strength Cond Res 28(9): 2391–2396, 2014—Minimal work has studied physical size effects on statistical performance among Major League players. In this study, longitudinal, bivariate, and regression analyses studied the impact of physical size on offensive baseball statistics within a homogeneous talent sample of Major League batting leaders. Body mass index (BMI) was calculated from heights and weights that were publicly available to form a statistical database of 4,360 offense leaders from 1950 to 2010. Repeated-measures analysis of variances examined differences in anthropometrics and baseball statistics between each decade from 1950 to 2010. Bivariate correlation and linear regression analyses evaluated BMI as an independent variable of influence, where all tests applied an a priori significance level (p ≤ 0.05). After 1980, offensive performance increased (p ≤ 0.05) concurrent to body mass and BMI growth (p < 0.001). During the 1960s, only batting average and on-base plus slugging percentages were found statistically decreased (p ≤ 0.05). All baseball statistics were positively correlated and predicted by BMI (p < 0.001). Consideration to covariant factors is required in data interpretation, yet nonetheless, our results showed physical size (BMI) to positively influence Major League offensive statistics. Over the 60-year period, greater body weight-to-height proportions owed to improved competitive performance, which suggests greater emphasis on hypertrophic stimuli in training and nutrition, as well as selection of larger professional baseball prospects.