Diuretic therapy (DT) plays a major role in disease management. However, one issue of concern in nutritionally vulnerable elders is that diuretic therapy also increases thiamin excretion, and little attention has been paid to the linkage between DT use and dietary intake of thiamin in this older population. The purpose of this study was to assess the relationship between DT use and dietary intake of thiamin in a randomly recruited sample of 342 homebound older adults. Baseline data, including three 24-hour recalls, were used to identify thiamin intake from food (15% < EAR and 33% < RDA), DT use (49%), and meal pattern (18% not regularly eating breakfast). Independent of sociodemographic and meal pattern variables, DT users (relative to non-users) were at increased odds for dietary thiamin intake < RDA (OR = 2.3) and < EAR (OR = 4.2). Considering the importance of home-delivered meals as a primary source of food assistance to homebound elders and that thiamin deficiency may exacerbate health problems, the results of this study suggest the need to include information on DT use as an integral component of program assessment for the targeting and monitoring of strategies to alleviate the risk for deficiency.