Dermatophilosis is a bacterial skin infection and wet conditions like, raining and dipping predispose sheep to it. A great economic loss can be caused by this disease because of its effect on the quality of wool. In Iran (near Saveh), there was an outbreak of the disease in a herd and the clinical manifestation was different from that of typical dermatophilosis. Diffuse wide alopecic area accompanied by large amount of purulent discharges were seen. The main lesions were located at the thoracic area. Secondary infection caused by Pseudomonas aeruginosa and bacteremia caused by staphylococcus was diagnosed and is considered to be the cause of 0.16% mortality.For diagnosis blood samples were obtained for CBC, and bacteriological culture and direct smear were taken from skin lesions. Biopsy was also prepared from skin lesions for histopathologic study and bacteriologic culture. Direct microscopic examination was made on Giemsa-stained smear prepared from crusts and their underlying tissue. Gram stained smear  was also prepared from underlying crusts of skin. After bacteriological and histopathological evaluation, Dermatophilus was determined. A typical railroad track of Gram positive bacteria was seen in Gram and Giemsa stained smear.  Filamentous bacteria in the epidermis were seen in histopathological samples. Infection was controlled by treating herd intramuscularly with 70,000 mg/kg BW procaine penicillin G, twice daily for 5 consecutive days.