BACKGROUND We assessed the relationship between body mass index and results of rehabilitation in stroke patients. MATERIAL AND METHODS The study was carried out at the Clinical Rehabilitation Ward with Early Neurological Rehabilitation Unit at the Clinical Hospital. The examinations were performed 3 times. Based on inclusion and exclusion criteria, 128 subjects were qualified for the first examination, the second examination involved 114 subjects, and 100 stroke patients participated in the third examination. Body mass was examined with an accuracy of 0.1 kg, using a Tanita MC-780 MA body composition analyser. Body mass index (BMI) was calculated for all of the subjects. Effects of rehabilitation were assessed with the Barthel index and Ashworth scale. RESULTS Higher functional status in daily life, measured with the Barthel scale, was found in patients with normal body mass, compared to the overweight and obese subjects (examination I, II, and II). Exam I showed that before rehabilitation the overweight patients obtained significantly higher results in assessment of upper limbs, based on the Ashworth scale (mean=0.35±0.54) compared to the obese patients (mean=0.03±0.32) and those with normal body weight (mean=0.24±0.75). CONCLUSIONS Following hospital-based rehabilitation, patients with normal body mass achieved greater functional efficiency. The findings also show a trend towards normalization of BMI. The positive effect of rehabilitation was sustained for 3 months (Exam III), which may contribute to decreased risk of cardiovascular diseases and complications such as stroke.