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Background and Objective: Considering the role of the hippocampus in memory, this study was done to evaluate the effect of 3-4,methylenedioxymethamphetamine on CA1 hippocampal neurons in male rats. Materials and Methods: In this experimental study 18 sprague dawley male rats (200-250g) were randomly allocated into three groups as follow: control (intact), control sham and experimental groups. Sham and experimental groups were received normal salin (1 cc) and MDMA10mg/kg IP for 7 days, respectively. Following transcardial perfusion by paraformaldehid 4%, structure and ultrastructure of right CA1 hippocampus were assessed by crysel violet staining and electronic microscope. Data were analyzed using SPSS-16, ANOVA and Tukey tests. Results: There was no significant difference between control (mean=210±40.38) and sham groups (mean=199±38.7) in neuron density. Neuron number decreased significantly in experimental group (mean=98±25.4) in compare to control and sham groups (P<0.001). There was no ultrastructural abnormality in control and sham groups. Finally, ultrastructural changes with apoptosis characterized by mitochondrial cristae reduction, distribution of nuclear chromatin and loss of cytoplasmic organelles in MDMA groups. Conclusion: This study shows that MDMA administration can stimulate the cell death with apoptotic pattern in hippocampus.