Laboratory results were reviewed for 47 patients who had skin lesions that had been simultaneously examined by viral culture and direct immunofluorescence for the presence of varicella-zoster virus. Immunofluorescence established the diagnosis in 24 of 28 patients (86%) strongly suspected on clinical grounds of having varicella-zoster infection. Viral culture was positive in only 10 of 28 patients (36%). Skin lesions in 19 patients who had other diagnoses were negative by both tests. Direct immunofluorescence appears to be a highly sensitive and specific technic for the rapid diagnosis of cutaneous varicella-zoster virus infections.