We evaluate the effectiveness of a sanitation marketing intervention aimed at increasing the supply of improved toilet products by local businesses and the household demand for toilets in rural Nigeria. Results from a randomized controlled trial show that treated businesses were more likely to produce and market the new toilet model and to engage in the sales of sanitation products more generally. However, we find no discernible impact on household toilet ownership rates. Evidence from interviews with sales agents employed by the business and responsible for about half of the sales suggest that inadequate incentives for sales agents and household affordability constraints may explain these results.