Significance: The purpose of this study was to see if a season of lacrosse practice and competition resulted in improvements in the fitness levels of girls on a middle school lacrosse team. Design: During the first week of the season, a middle school girls lacrosse team composed of 49 7th & 8th grade girls was tested. Pre-season testing occurred on two days and was done prior to the coaches making cuts to the roster. On day one, subjects performed three trials of the sit-and-reach test, total number of sit-ups completed in one minute, total number of modified pushups performed, three trials for a standing long jump and a 1.5-mile run. On day two, subjects completed a modified multistage shuttle run. Six weeks later, during the next-to-last week of the season, post tests were conducted and the subjects' height and weight were recorded. Practice (1.5 – 2 hours long) and competitions occurred during the school week with no interference from the researchers. Practices consisted of a period of conditioning, drills and playing lacrosse. A one-tailed dependent t-test was performed with alpha set at 0.01 level of significance. Results: Due to injuries, voluntarily choosing not to perform a test as well as being cut or resigning from the team, not all 49 players were tested for each dependent variable pre and post. Mean height was 159.5 + 7.9 cm. Mean weight was 52.3 + 12.6 kg. The value of each variable is presented pre-season and end of season with mean and standard deviation. Within the parenthesis is the number of players tested. Sit & Reach (41) = 49.3 + 4.8 cm and 49.5 + 5.3 cm. Sit-ups (39) = 39.3 + 9.5 and 43.3 + 7.4. Pushups (22) = 36.2 + 11.9 and 45.3 + 14.8. Long jump (32) = 153.2 + 14.2 cm and 168.4+ 12.2 cm. Shuttle run = 11.7 + 2.0 level and 14.6 + 1.7 level. 1.5 mile run = 789 + 62 seconds and 745 + 64 seconds. All changes are significant at the 0.01 level except sit & reach which is not significant. Discussion: This study indicates that 6 weeks of exposure to lacrosse practice and competition resulted in the improved fitness of the subjects as measured by several variables. It suggests that after school activities or sports such as lacrosse can have a positive influence on the health and fitness levels of middle school girls. Keyword(s): exercise/fitness/physical activity, youth sports