PURPOSE: to evaluate the effects of inspiratory muscle training (IMT) in adult sickle cell disease (SCD) patients in relation to respiratory muscle strength (RMS) variables; lung function; exercise tolerance; blood lactation concentration; limitation imposed by dyspnea in activities of daily living and; impact of fatigue on quality of life. METHODS: a randomized, single-blind study, with true load (TG) and sham load group (SG) design of IMT. Initial assessment included spirometry, volumetric capnography (VCap), and measurement of RMS by maximal inspiratory and expiratory pressure (PImax and PEmax). The Medical Research Council (MRC) dyspnea scale and the modified fatigue impact scale (MFIS) were also applied, and blood lactate concentration (Lac) was measured before and after the 6-minute walk test (6MWT). After this initial assessment, the patient used the IMT device at home daily, returning every 6 weeks for RMS reassessment. Both groups used the same device and were unaware of which group they were in. After a total period of 18 weeks, the patients underwent the final evaluation as initially performed.RESULTS: 25 patients in total participated up to the end of the study (median age 42 years). There were no significant differences between TG and SG groups based on age, sex, body mass index, severity of genotype. At the end of the training, in both groups there was a significant increase in PEmax and PImax, improvement in Vcap and in exercise tolerance and reduction of dyspnea in performing daily life activities. The same improvement was observed in patients grouped according to disease severity (SS and Sβ 0 vs SC and Sβ + ), without differences between groups. CONCLUSION: home-based inspiratory muscle training brings benefits to outpatients with SCD.