Objective: The aim of this study was to evaluate physical conditioning and muscle strength before and after a four-month program of physical training. Methods: Two groups of children, ages 8 to 11 years, with moderate asthma were studied. All subjects were tested before and after a program of physical training, which was conducted in 90-min sessions, twice weekly, for four months and also included exercises performed in the water. Children in both groups received general information about asthma, as well as information about the management and treatment of asthma. Results: In the final evaluation, anthropometric parameters (height and weight) were found to have increased. Children in the exercise group presented significant gains in the distance run in nine minutes (initial 1.333 + 0.03 km vs. final 1.440 + 0.03 km; p < 0.05), number of abdominal crunches (initial 24.3 + 1.4 abdominais vs. final 33.2 + 1.1; p < 0.05), maximal inspiratory pressure (initial 73 + 5 cmH2O vs. final 103 + 5 cmH2O; p < 0.05), maximal expiratory pressure (initial 75 + 4 cmH2O vs. final 102 + 4 cmH2O; p < 0.05) and heart rate at rest (initial 84.3 + 1.6 bpm vs. final 77.1 + 2.7 bpm; p < 0.05). The control group presented no significant changes in any of these parameters. Conclusion: An exercise program involving longer sessions, conducted less frequently, facilitates increased participation by children, thereby leading to better physical conditioning and greater muscle strength.