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Introduction : Cutaneous leishmaniasis is a public health problem in Iran. Actually Antimony compounds commonly used in the treatment of this disease. Using these drugs associated with limitations and several side effects. Research for introducing a new and effective drug is considere. In the present study, the effect of 5 - fluorouracil on growth of Leishmania major promastigotes were evaluated in vitro conditions. In addition the effect of fluorouracil on induction of apoptosis in promastigotes of the leishmania major were investigated. Material and Methods: Different concentrations of 5–fluorouracil(12, 25, 50 and 100 µg/ml) were tested in three times and the IC50 was calculated by counting the number of parasites. Viability percent of promastigotes was determined after adding drug by MTT assay. Flow cytometry was used to investigate the induction of apoptosis in the parasites. Findings: The 5–fluorouracil has inhibitory effects on the growth of Leishmania promastigotes.IC50 was measured 26.17 µg/ml after 24h. Analysis of the results of flow cytometry showed that the 5 - fluorouracil induces apoptosis in Leishmania major promastigotes. Discussion and Conclusion: The 5-fluorouracil has antileishmanial effects on leishmania major. So it can be suggested to evaluate in vivo condition against cutaneous leishmaniasis.