Protease was isolated from cotyledons of 5-day old marrow (Cucurbita pepo L.) seedlings. The enzyme was induced by kinetin or benzyladenine (BA) at 50, 100 and 150 µmol. Protease was also induced by homobrassinolide (HBL) after treatment with 0.2, 0.4, 0.6, 0.8 or 1.0 µmol. Polyamines such as putrescine, spermine, cadaverine, spermidine and mixture of polyamines induced protease activity. Ca²⁺, K⁺ and Mg²⁺ activated protease activity when tested at either 5 or 10 mM. On the other hand, Co²⁺, Zn²⁺, Al³⁺, Cu²⁺ and Hg²⁺ inhibited the enzyme activity. AMP, ADP and ATP induced protease activity. Surfactants such as Triton X-100, Tween 60 and Tween 80 increased protease activity when added in the range of 0.2-1.2 % (v/v). Treatment with various concentrations of CdCl₂ and PbCl₂ resulted in inhibition of protease activity and PbCl₂ was the stronger inhibitor. EDTA as chelating agent inhibited protease activity.