'Pranayama' or yogic breathing as a method of re-expansion of lungs in patients with pleural effusion was studied. Ten patients with pleural effusion practised alternate nostril breathing for 20 days after aspiration of fluid. An equal number matched for age and smoking habits underwent routine physiotherapy of the hospital for the same period. Lung function was measured: before aspiration; immediately after aspiration; and, 5, 10, 15 and 20 days after aspiration. The FVC, FEV1, MVV, PEFR, CE and RS, were used to measure lung function. The difference between the two groups in the gain in lung expansion as assessed by the above measures was tested for significance with appropriate nonparametric statistical tests at 0.1 level of significance. The results revealed that the patients practising Pranayama demonstrated a quicker re-expansion of the lungs in most of the measures of lung function. The findings are discussed in relation to implications for nursing care.