Several studies support hypolipidemic effect of fenugreek in normal and diabetic subjects. However, very little is known about the possible direct action of fenugreek on adipose tissue. The present study was designed to investigate the effects of fenugreek seeds on adipogenesis and lipolysis. Preadipocytes were isolated from adipose tissue of normal rats and differentiated to adipocyte in the presence of ethanolic extract of fenugreek seeds. The effect of this extract on lipolysis was also evaluated in fat tissue isolated from diabetic rats. Fenugreek led to a significant reduction in lipid droplet accumulation as evaluated with Oil Red O staining. Incubation of preadipocytes with the extract for 24 h resulted in significant decrease in cell viability. The extract, even at high concentrations (up to 1000 μg mL(-1)), had virtually no significant effect on lipolysis. The present data demonstrated that fenugreek seed inhibits formation of new differentiated adipocytes from precursor cells through an anti-proliferative effect on preadipocytes.