The objective of this study was to estimate the proportion of U.S. households with access to a residential swimming pool and the prevalence of adequate pool fencing. Data were collected using national cross-sectional telephone surveys in 1994 and 2001-03. Nearly 15% of households (16.3 million) reported access to a swimming pool at their residence (14.9%; 95% CI 14.1-15.7); only 74% were reported to be adequately fenced. Adequate pool fencing is associated with lower income, renting the residence, and residing in a building with multiple units or an attached house. An estimated 488,633 households with pool access, where the family owns the home and has children less than 5 years, were not adequately fenced. Between 1994 and 2001-03, the percentage of pools that were adequately fenced did not change substantially. This study highlights the need for continued efforts to target families with young children with drowning-prevention interventions that include and emphasize adequate pool fencing.