Efforts are under way nationally to reduce avoidable hospital readmissions by changing payments to hospitals, but it is unclear how well or how quickly these policy changes will produce widespread reductions in hospital readmissions. To examine some of the challenges to implementing such approaches, the authors analyzed the early experiences of 3 statewide programs to reduce preventable readmissions that began in 2009. Based on interviews with program participants in 2011, the authors identified 3 key obstacles to progress: the difficulty of developing collaborative relationships across care settings, gaps in evidence for effective interventions, and deficits in quality improvement capabilities among some organizations. These findings underscore the uncertainty of success of current readmissions policies and suggest that immediate improvement in readmission rates through a change in reimbursement may be unlikely unless these other obstacles are addressed expeditiously. In particular, cultivation of productive collaboration across care settings will be critical because these kinds of relationships are not well established or naturally occurring in most communities.