Clinical characteristics and immunoserological features of patients with overlap myositis treated in Clinic for Rheumatology of Military Medical Academy in the period 1978-1996 are presented in the study. Retrospective and partially prospective study included 16 patients with the diagnosis of dermatopolymyositis associated with some other systemic disease of connective tissue (SDCT) in overlap syndrome. There were 12-females of average age 37.33 years and 4 males of average age 52.25 years. Complete laboratory investigation included the determination of muscular enzymes values. Immunoserological analyses were also performed (RF, Le cells, ANA, ICs, immunoglobulins, cryoglobulins and complement), EMNG examination of pelvis and shoulder and pH examination of skin, subcutaneous tissue and muscles. The combination of the diseases was found in 11 patients, 7 were with PSS, 2 with SLE, 1 with RA and one with PAN. Three diseases were associated in 4 patients, SLE and RA in 2, PSS and RA in 1, thyroiditis and sicca complex in 1. Five-fold combination of disease was found in 1 patient. More frequent occurrence of fever, polyarthritis, skin manifestations, Raynoud's phenomenon, the involvement of serosas, lungs and heart, histological finding of skin and/or muscle vasculitis and larger presence of ANA, ICs, hypergammaglobulinemia and hypocomplementemia pointed out the dominant disorder of humoral immunity which was most probably connected with associated SDCT.