This study addresses the impact of vitamin D, energy balance and body composition on muscle soreness in active postmenopausal women. Purpose: This descriptive study was designed to assess vitamin D (diet and sun exposure) and energy balance in order to determine their effect on muscle soreness 48 hours after eccentric exercise. Methods: 29 healthy postmenopausal women (mean age: 59.1 ± 4.5 years) were recruited for this study. A 4-day diet/activity record was obtained and analyzed to estimate dietary vitamin D and energy balance (EB) in hourly increments. Total hours spent in EB < zero kcal and < - 400 kcal were calculated from the 4-day dietary log. A sun exposure questionnaire assessed the amount of vitamin D acquired as a result of sun exposure and skin exposed. Body composition was assessed with a multi-current Bioelectrical Impedance Analysis. Muscular strength was assessed with a 10 RM of the elbow flexors. Eccentric exercise was used to induce delayed onset muscle soreness of the elbow flexors. Participants recorded their level of perceived soreness pre and post exercise intervention on a visual analog scale. Spearman correlations evaluated associations between vitamin D and EB and soreness. Results: Soreness was not statistically significant with total vitamin D (p=1.0), EB < zero kcal (p=0.11) and EB < -400 kcal (p =0.50). Soreness was statistically significant with weight (p= 0.0), waist (p=0.04), hip (p=0.01), Body Mass Index (p=0.02) and VO2max (p = 0.05). Conclusions: These data suggest that adequate levels of vitamin D offer protection against muscle soreness 48 hours after. However, increase weight, waist, hip and BMI were related to increased soreness.