Costs to broiler producers associated with subclinical (mild) necrotic enteritis (SNE) were estimated using published information on impacts on body weight and feed conversion rate (FCR) associated with SNE and costs and revenues associated with broiler production. Estimates were expressed in U.S. dollars from the perspective of poultry producers. SNE was estimated to result in a 12% reduction in body weight and a 10.9% increase in FCR compared with healthy birds. For the purposes of this analysis, we considered scenarios involving hypothetical flocks of 20,000 birds raised to final body weights ranging from 4.63 to 7.94 lb. The incidence of SNE was assumed to occur at 20% based on the literature. For flocks raised for the length of time required to reach these target weights, SNE resulted in a loss to producers ranging from US$878.19 to US$1480.52 per flock. When feed costs required to obtain SNE flocks having a total live body weight equal to equivalent healthy flocks at market age were calculated, the increased cost to producers ranged from US$370.49 to US$739.38 per flock. SNE has the potential to cause a significant negative economic impact in broiler flocks. Strategies to reduce the incidence of SNE may help to increase the profitability of broiler production.