Xylopia aethiopica (Annonaceae) is used in some folk medicines and widely consumed as a spice in some parts of Nigeria. Its efficacy as an anti-androgenic substance has warranted the attention of African scholars. This study evaluated the enzymatic activity of lactate dehydrogenase (LDH), γ-glutamyl transferase (γ-GT), sperm quality (motility, count, morphology), testosterone level and histo-pathological changes of the testis of rats chronically treated with ethanolic extract of the pods (without seeds), seeds, and fruits (pods + seeds) of Xylopia aethiopica. Male Wistar (224–246 g) rats were treated with the extract of the pods, seeds, and fruits of Xylopia aethiopica at the dose of 0, 50, 100, and 200 mg/kg body wt. for 60 days. Serum biochemistry, sperm quality and histo-pathological examination of the testis were assessed for any treatment-related adverse effects. After treatment with Xylopia aethiopica, testosterone level was decreased dose-dependently in the animals treated with the seed extract compared to all other groups. The enzymatic activities of LDH and γ-GT were higher in rats treated with the seed and fruit extracts compared with those treated with the pods. The numbers of motile sperm, and counts were decreased while the numbers of sperm with morphological defects were higher in rats treated with the seed and fruit extracts compared to the control. Histopathological changes of the testis were also more severe in rats treated with the highest dose of the seed extract. We conclude that the compounds related to the anti-infertility effects of Xylopia aethiopica are present in the seeds. © 2016, Association of Clinical Biochemists of India.