This study examined seasonal variation in cardiovascular fitness and physical activity levels. It also examined the relationship between maximum oxygen uptake (VO2max) and scores obtained from physical activity and selfperception questionnaires. The study involved 83 elementary school students in grades 3-5. The Progressive Aerobic Cardiovascular Endurance Run (PACER) was used to determine cardiovascular fitness, while a questionnaire was used for reports of physical activity levels. There was no significant difference in VO2max or physical activity levels in regard to season. Although the relationship was weak (r=-0.074 to -0.262), the correlation between VO2max and Physical Activity Questionnaire for Children (PAQ-C) scores was negative in all three months for third graders only. No significant trends were found among fourth and fifth graders.