We have studied the chemomigration activity of an epithelial carcinoma cell line using a modified 96-well Boyden chamber apparatus consisting of upper and lower wells separated by an 8-microns pore polycarbonate filter. Cells from the malignant squamous carcinoma cell line A-431 were plated in the upper wells over a collagen IV-coated filter. In chemokinesis assays, the cells were allowed to migrate toward NIH 3T3 fibroblast-conditioned medium or control media in the lower wells for 6 hours at 37 degrees C with 10% CO2. A-431 cells preferentially migrate across the barrier toward conditioned media but not control media. Control normal keratinocytes showed no migration. A highly metastatic melanoma cell line and poorly metastatic melanoma cell line, in which chemomigration has been shown previously to correlate with metastatic potential, were used as positive and negative cellular controls. This system provides a rapidly quantifiable method by which the invasion characteristics of multiple cell lines can be studied simultaneously in a single assay using the 96-well format.