Pesticide synergism has been defined as the simultaneous action of two or more compounds in which the total response of an organism to the pesticide combination is greater than the sum of the individual components. Theoretically, when fungicides interact synergistically, a high level of disease control is achieved with less than label rates of each component fungicide. More pronounced synergistic effects reportedly occur between fungicides with different modes of action, although synergy also has been described between certain fungicides with a similar mode of action (DeWaard, 1996). Many of the investigations that address synergy in fungicide mixtures have been limited to laboratory studies with cultures of fungal pathogens (DeWaard and Gisi, 1995). However, some published studies demonstrate synergistic interactions between fungicides at the field level (Couch and Smith, 1991). Published work on fungicide synergism against dollar spot is limited to a single popular article (Couch, 2002). Our work represents a practical examination of synergism among fungicides for dollar spot control on creeping bentgrass