Introduction Patients who suffered severe COVID-19 need pulmonary rehabilitation. Training may be prescribed objectively based on the maximum speed in the six-minute walk test. The objective of this study was to determine the effects of a personalized pulmonary rehabilitation program based on the six-minute walk test speed for post-COVID-19 patients. Methods Observational quasi-experimental study. The pulmonary rehabilitation program consisted of 8 weeks of training, twice a week for 60 minutes per session of supervised exercise. Additionally, the patients carried out home respiratory training. Patients were evaluated by exercise test, spirometry and the Fatigue Assessment Scale before and after the eight-week pulmonary rehabilitation program. Results After the pulmonary rehabilitation program, forced vital capacity increased from 2.47 ± 0.60 to 3.06 ± 0.77 L (p < .001) and the six-minute walk test result increased from 363.50 ± 88.87 to 480.9 ± 59.25 m (p < .001). In fatigue perception, a significant decrease was observed, from 24.92 ± 7.01 to 19.10 ± 7.07 points (p < .01). Isotime evaluation of the Incremental Test and the Continuous Test showed a significant reduction in heart rate, dyspnoea and fatigue. Conclusion The eight-week personalized pulmonary rehabilitation program prescribed on the basis of the six-minute walk test speed improved respiratory function, fatigue perception and the six-minute walk test result in post-COVID-19 patients.