A series of 2,4,6-trisubstituted pyrimidines and 1,3,5-triazines have been synthesized and screened for their in vitro and in vivo antileishmanial activity against Leishmania donovani. Among all, 14 compounds have shown promising inhibition of 80-100% at 10 microg/ml against promastigotes and IC(50) in the range of 0.89-9.68 microg/ml against amastigotes. Three compounds 13, 32 and 33 with good selectivity index (S.I.) were screened for their in vivo activity in golden hamsters (Mesocricetus auratus) infected with MHOM/IN/80/Dd(8) strain of L. donovani and have shown moderate in vivo inhibition of 48-56% at a dose of 50 mg/kg x 5, i.p. route for 5 days.