Plantain chips (Musa sapientum L.) were infested with Tribolium castaneum Herbst in the laboratory (64 ± 5% relative humidity and 30 ± 2°C temperature) to evaluate physical and biochemical losses of the chips due to pest damage. Varying levels (4, 8 and 12) of T. castaneum adults were introduced into 20 g plantain chips. An uninfested 20 g of chips served as the control. At 2 and 4 months after infestation (MAI), data on weight loss of chips and the cumulative number of T. castaneum adult, were taken. The samples were then analyzed for proximate and mineral element composition. Infestation level affected weight loss and final insect count. When chips were stored for 2 months, 7.3 cumulative adults obtained in a sample infested with 12 adults was significantly higher than the 4.0 adults obtained in a sample infested with 4 adults. When stored for 4 months, 5.3% weight loss due to 12 initial adults was significantly higher than weight loss recorded in other lower levels of infestation. The proximate analysis revealed that dry matter, ash and crude fibre were significantly reduced with storage period and initial insect level. Fat, crude protein and moisture increased with infestation level and storage period. In uninfested plantain chips, calcium level was not affected with storage period, while phosphorous and iron were significantly reduced with storage period. Both, the level of infestation and storage period, caused significant reduction of the studied mineral elements. There was an interactive effect of the storage period and infestation level for all studied parameters in the biochemical analysis.