The zymography assay is a semiquantitative polyacrylamide gel electrophoresis technique that allows the separation of matrix metalloproteinases (MMPs) by molecular weight/charge and their detection through their ability to degrade substrates such as collagen (gelatin). The presence of MMPs can be analyzed in cell lysates and conditioned media, observing degradation bands of the gel copolymerized with gelatin. In addition, the size of the degradation bands present in the gel allows comparing the relative presence of MMPs in the analyzed samples. It is a simple and affordable method for the analysis of processes associated with tumor invasion.