Yoga is a physical and mental discipline that forms part of Ayurvedic medicine, a comprehensive and ancient holistic health system. Given the limited information available on the hematological and biochemical changes associated with the extended practice of yoga, the purpose of the present study was to examine the effects of long-term yoga practice (more than three years) on blood parameters. Twenty-six healthy volunteers of whom sixteen were advanced practitioners of yoga took part in the study. The remaining ten participants were not practitioners and constituted the control group. Blood samples were taken to determine the following hematological parameters: erythrocytes, hematocrit, hemoglobin, platelets and erythrocyte sedimentation rate; and biochemical parameters: renal and hepatic profile, glucose, uric acid, total protein and albumin. The Mann-Whitney U test was performed to ascertain the statistical analysis. The experimental group showed higher hemoglobin levels (p>0.01) and erythrocyte sedimentation rate (p>0.01) and lower albumin levels (p>0.05). The regular practice of yoga brings about changes in basic hematological parameters. New clinical trials with a wider sample of subjects will be needed in order to recommend the use of yoga as a complementary therapy in those cases where the above-mentioned parameters are altered.