Sclerotinia homoeocarpa is a common and severe fungal pathogen responsible for dollar spot disease on turfgrasses. The RAPD–PCR technique was used to identify genetic variation among 26 isolates of S. homoeocarpa. DNA polymorphisms were detected among different isolates using 15 oligonucleotide primers and a dendrogram was constructed using the unweighted pair-group method with arithmetic averages (UPGMA) for cluster analysis. Isolates from different geographical locations in the United States were separable into three distinct groups based on RAPD profiles and the cluster analysis. These three groups, however, were clearly more closely related to each other than to the isolate from Belize which was unique compared to the other S. homoeocarpa isolates examined. RAPD profiles suggest that transport of the pathogen from east coast to west coast locations in the U.S.A. may account for the recent identification of the disease in the Pacific Northwest. The results indicate that RAPD–PCR is a valuable method for differentiating isolates of S. homoeocarpa.