The presence of megacapillaries and a decreased capillary density are the hallmarks of the scleroderma capillary pattern, which can be detected by nailfold capillarmicroscopy. One hundred and eighty-six patients with Raynaud's phenomenon, 65 cases with undifferentiated connective tissue disease (UCTD), 47 patients with systemic lupus erythematosus (SLE), 26 patients with dermato/polymyositis, 14 with rheumatoid arthritis, seven cases with primary Sjögren's syndrome and 102 patients with systemic sclerosis (SSc) were investigated. Of the 16 patients with diffuse cutaneous SSc and the 86 limited cutaneous SSc cases, 14 (87.5%) and 53 (61.6%) showed the scleroderma capillary pattern, respectively. Nine of the 65 (13.8%) cases with UCTD and 24 of the 186 (12.9%) cases with Raynaud's phenomenon also exhibited the same pattern. Four of the 47 (8.5%) with SLE and seven of the 26 (26.9%) with dermato/polymyositis, and no patients with rheumatoid arthritis or Sjögren's syndrome, exhibited the scleroderma capillary pattern. The conclusion is that the scleroderma capillary pattern is often present in SSc and dermato/polymyositis. Furthermore, patients with Raynaud's phenomenon and UCTD may also occasionally exhibit this pattern. Therefore, capillarmicroscopy seems to be a useful tool for the early selection of those patients who are potential candidates for developing scleroderma spectrum disorders.