A minor modification of a mammalian cytogenetic technique allows excellent cytologic preparations of chromosomes and nuclei from either the gonads or somatic cells of both large and small insects. This method can also be used for autoradiographic investigations.This communication describes a method for excellent cytological preparations of both chromosomes and nuclei from the gonads of grasshoppers and from the brain tissue of mosquito larvae without recourse to manual squashes or histological sections. The method was developed with a slight modification of the techniques used in mammalian chromosome preparation (Hsu and Pomerat 1953; Rothfels and Siminovitch 1958, Moorhead, Nowell, Mellman, Battips and Hungerford 1960, and Tarkowski 1966). This procedure can be applied to study all stages of meiosis in both testes and ovaries of grasshoppers and locusts; as well as mitosis from the brain cells of fourth instar mosquito larvae (prepupae) and is readily adaptable for autoradiographic investigations.