Phthalates are diester derivatives of phthalic acid widely used in many commercial applications. The aim of this study is therefore to evaluate possible genotoxicity of di-n-hexyl phthalate (DHP) and dicyclohexyl phthalate (DCHP) at different concentrations using single-cell gel electrophoresis (comet) and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end-labeling (TUNEL) assays in testes samples of male rat pups. DCHP and DHP in corn oil were administered to the pregnant rats by gavage at the doses of 0 (vehicle), 20, 100, and 500 mg kg(-1) day(-1) from gestational day 6 (GD6) to GD19. After delivery, male rats were allowed to grow until prepubertal, pubertal, and adulthood. At necropsy, the blood samples were collected from heart and were excised immediately. The apoptotic cells of prepubertal, pubertal, and adult testis were detected using TUNEL assay. The comet assay was performed on blood lymphocytes and testes samples of adult male rats. The comet assay results showed that tail length, tail intensity, olive tail moment (OTM), and percentage of DNA present in tail were higher when DHP content was increased. Judging from the values of OTM and percentage of DNA, DHP could significantly induce DNA breakage at doses of 100 and 500 mg kg(-1) day(-1) compared with the control group. An increase in TUNEL-positive cells of prepubertal, pubertal, and adult testicular cells was observed in the treated groups. In conclusion, prenatal exposure to DHP and DCHP may possess genotoxic risk to testicular cells of rats at all stages of development, even at adulthood.