A feeding trial was conducted to evaluate the effect of pawpaw-onion powder (POP) mixture on the growth, and haemato-biochemical and antioxidant responses of Clarias gariepinus (4.02 ± 0.01g/fish) for 60 days. Five trial diets were formulated as control (without POP or antimicrobial growth promoter (AGP)), AGP (basal diet + 10ml AGP/kg diet), POP 2.5 (basal diet + 2.5g POP/kg diet), POP 5.0 (basal diet + 5.0g POP/kg diet) and POP 10 (basal diet + 10g POP/kg diet). Two hundred and twentyfive fish were equally distributed into five groups in triplicate and fed twice daily.The results indicate that AGP or POP supplementation exerted no effects on the growth and blood profile among the various groups, but a significantly higher lymphocyte count was observed in POP 10g/kg. The highest whole-body protein and lipid contents were noticed in fish fed the control diet (p < .05), whereas POP 5.0g/ kg group recorded the highest hepatosomatic value. Furthermore, the cholesterol level was found to be lower in the AGP-and POP-fed fish compared with the higher level recorded in the control. The glucose concentration and superoxide dismutase enzyme activity were found to be higher in POP 2.5-fed fish, whereas POP 10-fed fish showed higher catalase activities compared with other groups (p < .05). Based on the result obtained, this study showed that dietary POP had no significant impact on the growth performance but has direct effects on the whole-body lipid content, lymphocyte count, cholesterol level, alanine aminotransferase, alkaline phosphatase and antioxidant response of Clarias gariepinus. K E Y W O R D S blood profile, Clarias gariepinus, onion peel, pawpaw seed, serological indices How to cite this article: Fawole FJ, Adeoye AA, Tiamiyu LO, Samuel FC, Omosuyi OM, Amusa MT. Dietary combination of pawpaw seed and onion peel powder: Impact on growth, haematology, biochemical and antioxidant status of Clarias gariepinus. Aquac Res. 2020;51:2903-2912. https://doi.