Chancroid is a sexually transmitted disease that is not often recognized in the United States. It has traditionally been treated with sulfonamides and/or tetracyclines. Recently, 14 active-duty U. S. Army personnel who acquired chancroid in the Far East were seen at the Madigan Army Medical Center, Tacoma, Wash. All of the organisms were isolated from clinical material on solid media without the use of a blood-clot tube. Because of dissatisfaction with conventional treatment and the demonstration of in vitro sensitivity of the organism to erythromycin, seven of the last eight patients were treated with erythromycin. All patients treated with erythromycin had rapid and favorable responses and none suffered recurrences. The results of this study led to three conclusions: chancroid is a relatively common disease in the Far East, the causative organism can be isolated by most clinical microbiology laboratories with proper technique, and erythromycin is an effective drug in the treatment of chancroid.