Abstract: Four groups of hamsters infected with Leishmania donovani were treated with primaquine, 8-piperazinyl aminoquinoline, chinocide, and 8-morpholinyl aminoquinoline per os. The count of parasites in the smears of liver and spleen was made 3 clays after the completion of treatment for evaluating the therapeutic action. It was shown that 8-Fiperazinyl aminoquinoline had a high, and primaquine a low, therapeutic activity, while the other two compounds were ineffective. Various concentrations of 8-piperazinyl aminoquinoline anti primaquine in normal saline were used in vitro for determining the leishmanicidal effect on leptomonas of Leishmania donovani. It was found that the two derivatives exerted a complete killing effect in 48 hours at the concentrations of 1:4,000 and 1:6,000 respectively.