Context The cost of feedstuff such as maize and other conventional energy sources has increased due to high competitive demand, which necessitated the search into alternative feedstuff such as cassava by-products (peel and leaf). However, their nutrient availability is hampered by antinutritional factors and constituent fibre. Aims This study investigated the effect of dietary inclusion of differently processed cassava peel–leaf blend (CPLB) on performance, carcass yield, organ weights and ileal microflora of growing pigs. Methods Cassava peel:cassava leaf (CPLB; 5:1) was included in the pigs’ diet in a feeding trial for 16 weeks. The CPLB replaced maize at 100%. Twenty-four pigs of mean weight range (20–22 kg) were assigned on a weight-equalisation basis to four dietary treatments having six replicates, with one pig per replicate. A standard corn soya-based diet (control), unfermented CPLB (UCPLB), water-fermented CPLB (WCPLB) and microbial-fermented CPLB (MCPLB) using Aspergillus tamarii as the inoculum was formulated. Performance was measured weekly, while carcass yield, organ weights and ileal microbial count were measured at the end of the 16th week. Key results Dietary inclusion of WCPLB and MCPLB reduced (P < 0.05) carcass weight. Pigs fed control diet and those fed diet containing UCPLB had a similar dressing percentage, while those fed diet containing MCPLB had an intermediate dressing percentage to those fed control diet and those fed diet containing WCPLB. Reduced (P < 0.05) Escherichia coli count (3.30 and 3.36 log10) was obtained in the ileum content of pigs fed diet containing UCPLB and WCPLB respectively. Conclusion Dietary replacement of CPLB for maize did not affect performance of pigs significantly and inclusion of UCPLB in the diet of pigs resulted in a comparable dressing percentage that for pigs fed control diet. Implication This study will help researchers on the right combination of the by-product without detrimental effect on carcass yield, and also encourage the farmer on utilisation of the by-product in pig feeding.