Fibromatosis or desmoid tumour is a benign fibroblastic proliferation with aggressive infiltrative growth. High incidence of recurrence is noted after incomplete resection of the involved margins of the lesion. Pelvic fibromatosis is a rare condition and usually affects females. Patients frequently complain of pelvic pain, which can mimic gynaecological abnormalities. A case of pelvic fibromatosis involving pelvic floor muscles with unchanged appearance during 5 years of follow-up is presented.