In a retrospective study covering 11 years, 59 adult cases of dermatomyositis or polymyositis were reviewed. The disease was of paraneoplastic origin in 9 cases (15,25 p. 100), the same proportion as that found in the literature (14,6 p.100). The striking female predominance (8/9 cases) and the patients' mean age (61.11 years) were higher than those noted in non-paraneoplastic dermato- and polymyositis in adults (female predominance 34/50, mean age 52.9 years). Clinically, out of 9 patients 7 had dermatomyositis and 2 had polymyositis. The disease was discovered at the same time as the neoplasia in 7 of the 9 cases. Muscle histology showed that in contrast with non-paraneoplastic cases of dermatomyositis-polymyositis those of paraneoplastic origin had moderate lesions without fibrosis.