Epidermal nuclear deposits of immunoglobulins (Ig) were studied by direct immunofluorescence in three groups of patients: ten scleroderma (SD, systemic sclerosis), seven dermatomyositis (DM) and seven systemic lupus erythematosus (SLE). Each patient had skin biopsies taken from three different sites (nailfold, forearm, buttock) on the same day that a serum sample was also obtained. Epidermal nuclear deposits were observed in nine of twenty-four patients (five SD, two DM, two SLE). A high serum ANA titre correlated significantly with the presence of epidermal nuclear Ig deposits. The nucleolar epidermal nuclear pattern was limited to the SD group, four of ten patients showing this pattern. Two of nine patients with positive results in the nailfold and forearm had negative findings in the buttock, supporting the view that deposition of Ig in the epidermal nuclei occurs in vivo.