Matrix metalloproteinase 9 (MMP-9), able to degrade type IV collagen, plays a key role in inflammatory cell migration as well as in the destructive behaviour of cholesteatoma. The aim of our study was to compare the expression of MMP-9 and TIMP-1 in cholesteatoma tissue and in the concentrations in serum and plasma concentrations.Twenty five adult patients suffering from cholesteatoma (a study group) were included in the study. A comparison group consisted of 25 adult patients admitted to hospital due to nasal septum deviation. MM-9 and TIMP-1 serum and plasma concentrations as well as proteins' expressions in cholesteatoma tissues (study group) and normal retroauricular skin specimens (control group) were evaluated. MMP-9 and TIMP-1 concentrations were measured using enzyme-linked immunosorbent assay (ELISA). Cholesteatoma tissues and normal retroauricular skin specimens were evaluated immunohistochemically.In the study and a comparison groups, MMP-9 and TIMP-1 concentrations were similar with no significant difference within the groups. In cholesteatoma tissues, the expression of the investigated enzyme and its inhibitor was higher than in normal skin specimens, limited mostly to cholesteatoma perimatrix.Cholesteatoma may be limited to the middle ear or parts of the temporal bones. Our findings suggest better clinical usefulness of MMP-9 and TIMP-1 expression in cholesteatoma tissues than either serum or plasma levels of these proteins. It might suggest that the higher the expression of MMP-9 the stronger the inflammation -accompanied cholesteatoma.