A B S T R A C TObjective: To ascertain the functional integrity of renal and hepatic tissues of Wistar rats fed with processed cocoa bean-based beverages and raw cocoa bean products-containing diets by using biochemical and histological methods. Methods: Thirty Wistar rats were designated on the basis of experimental diets which were given for 28 days. At the end of the feeding period, blood samples were drawn, and renal and hepatic tissues were excised from the experimental rat groups for functional tests and histological examinations, respectively. Results: Serum alanine aminotransferase activities of the experimental rat groups showed no significant difference (P > 0.05) and were within a relatively narrow range of (32.17 ± 4.98) IU/L to (41.00 ± 10.85) IU/L, whereas serum aspartate aminotransferase activities gave wide variation within the range of (15.67 ± 2.13) IU/L to (34.83 ± 8.31) IU/L with P < 0.05. Serum bilirubin concentrations of experimental rat groups were less than 1 mg/dL. Serum total protein and albumin concentrations varied within a relatively narrow range. Serum creatinine concentration was significantly lower (P < 0.05) than serum urea concentration. Histology showed evidence of moderate disarrangement of hepatic tissue architecture and degenerated tubules as well as glomerular turfs. Conclusions: The pattern of alanine aminotransferase activity being more active than aspartate aminotransferase one in serum appeared to correlate with the extent of disarrangement of hepatic tissue architecture. The experimental rat groups exhibited no hyperbilirubinemia. Also, diets containing processed cocoa bean and raw cocoa bean products did not substantially interfere with the capacity of the hepatocytes to biosynthesize plasma proteins and the functionality of renal tissues.