Abstract: Investigations were carried out to study the inhibitory effects of Albizia saman’s leaf extracts on the germination and growth behavior of agricultural crops e.g. Brassica juncea (L.) Czern and Coss; Phaseolus mungo L.; Raphanus sativus L.; Vigna unguiculata (L.) Walp. And Cicer arietinum L. The experiments were conducted in sterilized petridishes with a photoperiod of 24 h at room temperature of 27-280C. The effects of the different concentrations of aqueous extracts were compared to distill water (control). The aqueous extracts of leaf caused significant inhibitory effect on germination, root and shoot elongation and development of lateral roots of receptor plants. Bioassays indicated that the inhibitory effect was proportional to the concentrations of the extracts and higher concentration (50-100%) had the stronger inhibitory effect whereas the lower concentration (10-25%) showed stimulatory effect in some cases. The study also revealed that inhibitory effect was much pronounced in root and lateral root development rather than germination and shoot growth.