To investigate the histological and immunohistochemical effects of aqueous leaf extract of Xylo- pia aethiopica on the pancreas in streptozotocin-induced diabetic rats, 30 adult Wistar rats were divided into three groups (n=10). Group A was the control (administered with equivalent vol- ume of citrate buffer), group B animals were made diabetic by a single intraperitoneal injection of streptozotocin dissolved in citrate buffer (65 mg/kg), group C animals were made diabetic as above and treated with 200mg/kg body weight of aqueous leave extract of Xylopia aethiop- ica for 25 days. Upon animal sacrifice, the pancreas were excised, fixed in 10% formol saline and processed for light microscopy and immunohistochemistry.. The results revealed destruc- tion of the islet cells in the untreated diabetic group as compared with the controls. The extract treated group was characterized by recovery/regenerative processes indicated by improvement in islet morphology. In untreated diabetic rats immunoreactive P-cells were sparse, at variance from the controls. The group treated with aqueous leaf extract of Xylopia aethiopica revealed more intense staining for insulin and significant (p<0.05) increase in the percentage of immuno- labelled surface area when compared with the untreated diabetic group, suggesting the ability of P-cells to secrete insulin in the extract treated rats. We conclude that the aqueous leaf extract of Xylopia aethiopica improves recovery process of P-cells in streptozotocin-induced diabetic rats and might become useful in the management of diabetes related complications.