A non-microtubule-based spindle matrix has been observed in Drosophila melanogaster meiotic and somatic cells. This matrix comprises the proteins: Skeletor, Megator and Chromator, which localize to the nuclear periphery and chromosomes at prophase and to the microtubule spindle during mitosis and meiosis. This matrix might play a role in nuclear organization and microtubule assembly and stabilization. It is important to determine the presence or absence of this matrix in other species in order to compare form and function to that in Drosophila. These matrix proteins were studied in both normally dividing cells and cells in which division was disrupted. Our evidence suggests that a spindle matrix exists in meiocytes and embryos of the cricket, Acheta domesticus, and in a mammalian cell line established from Chinese hamster ovary cells. We report the results of our studies on the spindle matrix in invertebrate and mammalian cells and discuss implications of these findings.