As the prevalence of obesity rapidly climbs among youth in the United States, public health practitioners and policymakers seek effective means of slowing and reversing these trends. Recently, many state laws and regulations addressing childhood obesity have been introduced and enacted. Understanding determinants of such legislation may inform the development and passage of future policies. For this study, key-informant interviews were conducted with 16 legislators and staffers from 11 states in 2005-2006 to examine qualitative factors that enable and impede state-level childhood obesity prevention legislation. Commonly cited factors positively influencing the passage of childhood obesity prevention legislation included national media exposure, introduction of the policy by senior legislators, and gaining the support of key players including parents, physicians, and schools. Noteworthy barriers included powerful lobbyists of companies that produce unhealthy foods and misconceptions about legislating foods at schools. Although the total number of informants was modest, their valuable insights provide policymakers and practitioners with a set of enablers and barriers to be considered when pursuing state-level policy.