The effect of type III collagen, an extracellular matrix protein, on the in vitro migration and invasion of glioblastoma cells was assayed by chemotaxis using four cell lines. Migration and invasion of gliomablastoma cells was observed in the presence of varying concentrations of type III collagen. In contrast to control experiments in which the protein was not added, type III collagen significantly increased migration and invasion of glioblastoma cells in a dose dependent manner up to 10 micrograms/ml; however, higher concentrations of the protein eliminated this affect on migration and invasion as did the presence of a monoclonal type III collagen antibody. Type III collagen was also shown to stimulate the migration of glioblastoma cells from spheroids to monolayers. The results of this study indicate that type III collagen does influence the migration and invasion of human glioblastoma cells in vitro.