Insect mandibles are most frequently encountered fragments in processed foods. Thanks to their sclerotised and darkly pigmented nature, they usually remain intact in foods and are relatively easily detectable. Moreover, because of their complexity and variety of shapes, stored product beetle mandibles may be useful in species determination. The present work deals with a comparative morphology of two stored product bostrichid beetles, Rhyzopertha dominica and Prostephanus truncatus. The mandibles were studied using by light and scanning electron microscopy and their morphological details, overall appearance and size are provided.Insect mandibles are most frequently encountered fragments in processed foods. Thanks to their sclerotised and darkly pigmented nature, they usually remain intact in foods and are relatively easily detectable. Moreover, because of their complexity and variety of shapes, stored product beetle mandibles may be useful in species determination. The present work deals with a comparative morphology of two stored product bostrichid beetles, Rhyzopertha dominica and Prostephanus truncatus. The mandibles were studied using by light and scanning electron microscopy and their morphological details, overall appearance and size are provided