A single dose complete crossover study of captopril (25 mg) conventional formulation to be marketed in India was carried out in 8 eight healthy human male volunteers. The formulation was compared with a standard international formulation of captopril (25 mg). Plasma samples were analysed for captopril using the indirect method of Angiotensin I radioimmunoassay (RIA). Pharmacokinetic parameters such as C(max), T(max), AUC0-12, AUC0-(∞), AUMC0-12, AUMC0(-∞), MRT0-12, MRT0(∞), halflife (1) and halflife (2) were determined and were subjected to statistical analysis. During the study, no undesirable side effects were observed in any of the volunteers.