The influence of packaging materials on infestation by Tribolium castaneum (Herbst) in wheat flour was investigated under laboratory conditions at 27 ± 2and 75 ± 5% relative humidity. The tested packaging materials included vacuum-sealed plastic bags, aluminum foil bags, non-woven cloth bags, kraft paper bags, and plastic compound bags. When T. castaneum adults were released on packaged wheat flour, the degree of infestation varied depending on the packaging materials. The highest infestation was observed in refined wheat flour packaged with plastic compound bags (mean 46 ± 20 insects). For the flour packaged with non-woven cloth bag and kraft paper bags exposed to adults, insect infestation was nil or negligible (mean population < 3 ± 1 insects). For the flour packaged with aluminum foil bags and vacuum-sealed plastic bags exposed to adults, insect infestation was nil. Damage to the packaging materials along the edges or on the upper surfaces was observed in non-woven cloth bags and plastic compound bags. Aluminum foil bags and vacuum-sealed plastic bags offered the best protection against T. castaneum adults.