Twenty four N~1- 4-3-(dialkylamino) methy 1-, and 3,5-bis(dialkylamino) methyl]-4-hydroxyanilino]-6-trifluoromethyl-2-pyrimidinyl]-N~3-(4-halogenophenyl) guanidines (1) had been synthesized and screened witn Litemosoidos carihii. They were found to possess microfilaricidal and/ or macrofiaricidaleffects.