This thesis is designed to explain the unordinary amount of left-handed hitters found in Major League Baseball (MLB). The focus of this study is to determine the appropriate amount of left-handed hitters a MLB team should employ in order to maximize their success. The driving force behind this study is that the average amount of lefties in MLB is substantially higher than the amount of lefties found in everyday society. The hypothesis is that a team should employ between 33% and 55% of their hitters to be lefthanded in order to achieve a team's optimal rate of success. This study will include all 30 MLB baseball teams over the span of ten years including more than 4100 hitters. Two models will be used to link the effect left-handed hitters have on the total number of runs a team scores, and also a team's season long winning percentage. The regressions produced R-squared values of .91 and .45 respectively. While the model was able to prove several different variables do significantly affect runs scored, and winning percentage the results were inconclusive in relating left-handed hitting to either dependent variable. For that reason the research could not support the hypothesis that MLB teams should employ between 33% and 55% left-handed hitters.