Introduction. Indoor cycling training programs at fitness clubs offer the possibility of optimizing the structure and amount of physical activity, which reduces the risk of disrupting the adaptive abilities of women’s bodies. The main purpose of this study was to identify the effect of an indoor cycling program on the body composition and physical fitness of young women.Material and methods. Twenty-nine women (age = 29.31 ± 3.40 years, body weight = 70.71 ± 6.15 kg, and height = 169.83 ± 3.17 cm) took part in the study, participating in three classes per week for 16 weeks. Each class included three periods: the preparatory, main, and supporting periods. Body composition (waist circumference and body mass index), cardiorespiratory fitness (VО2max), motor fitness (balance), and musculoskeletal fitness (upper and lower body muscle strength and muscular endurance) were compared before the beginning of the study and after 10 and 16 weeks of training. Changes recorded in each variable over time were analyzed statistically using repeated measures methods.Results. Significant improvements in physical fitness were identified in the values of the body mass index (7.81%; ES: 0.95, p = 0.0001) and VО2max (12.51%; ES: 1.02, p = 0.0001). Moderate improvements were found in lower body muscle strength (11.13%; ES: 0.66, p = 0.0001) and waist circumference (6.05%, ES: 0.65, p = 0.0001). There was an increase in the strength of the muscles of the upper body (5.27%; ES: 0.41, p = 0.0001), muscular endurance (8.20%; ES: 0.32, p = 0.0001), and balance (10.68%; ES: 0.29, p = 0.003).Conclusion. Indoor cycling in a fitness club is an effective form of exercise for young women; it has targeted training effects on the body’s functional systems, adaptive abilities, and physical fitness.