Treadmill training in children with chronic respiratory diseases: Clinical series Introduction: Chronic respiratory diseases (CRD) in children have increased in recent years. Respiratory Rehabilitation is one of the treatments used in this population. Objective: To evaluate the impact of a treadmill training program over pediatric patients with CRD in the Josefina Martínez Children's Hospital at Santiago de Chile. Methods: Retrospective cases series with prospective record of 9 patients 7.1 ± 3.9 years-old with CRD and treadmill training. The patients performed 24 sessions. The Pre-post records of the 6-minute walk test (6MW) and the maximum speed obtained in the Incremental Load Test (ILT) were analyzed. Results: Averages of the distance traveled pre and post-training were 383 ± 142.4 meters and 451.7 ± 142.4 meters respectively (p < 0.0001). The average maximum speed obtained in the ILT was 4.1 ± 1.1 km/h and 5.4 ± 1.27 km/h (p = 0.001). Conclusion: The distance walked in the 6-minute walk test and the maximum work capacity improve significantly with treadmill training in these patients with CRD.