The escape of malignant cells from primary tumour and their active migration to the surrounding tissues are among the most important steps in the metastatic process. During migration, tumour cells interact with neighbouring neoplastic and normal cells and such interactions may affect their motile activity. We investigated the effect of extracellular calcium ions on migration of mouse melanoma B16 cells stimulated by homotypic cell-to-cell contacts. It was found that the decreasing of extracellular Ca2+ influx into B16 cells by lowering Ca2+ concentration in culture medium, or by the application of 0.5 mM La3+ (non-selective inorganic Ca2+ channels blocker), reduced the contact-mediated acceleration of migration of melanoma cells but only slightly affected the basal motile activity of non-stimulated single, separated cells moving without contacts with neighbouring ones in sparse culture. Since it was suggested that contact-mediated acceleration of migration of melanoma B16 cells may be controlled by mechanosensitive and/or voltage-gated ion channels, the presented data support the concept that these channels may affect cell migration by regulation of extracellular Ca2+ influx into stimulated cell.