The baculovirus expression system was used to produce recombinant human matrilysin. Expression of promatrilysin reached a peak at 72 h post-infection. Most of the recombinant protein remained in the intracellular fraction in an insoluble form, which after renaturation was purified by S-Sepharose and Green A Dyematrex chromatography in order to remove host proteases. Active recombinant matrilysin degraded casein, type T and type IV collagens and fibronectin. Expression of recombinant human matrilysin using the baculovirus system represents a useful tool for obtaining large amounts of this metalloproteinase in order to carry out further biochemical studies and to screen for inhibitors.