Using 2-year panel data, this study examined (1) whether experiencing financial hardship associated with out-of-pocket medical expenditures affected delaying/missing necessary health care in the following year; (2) whether such financial hardship mediated the effects of predisposing, enabling, and need characteristics on timely health care access (i.e., significant indirect effects); and (3)whether such mediating effects are different by chronic health status (i.e., moderated mediation) among U.S. adults. The 2011 National Health Interview Survey was linked to the 2012 Medical Expenditure Panel Survey. The sample includes 8,993 adults aged between 26 and 64 years. Among them, 1,089 reported having at least one chronic health condition that had caused activity limitations. Multiple-group path analysis was conducted using Mplus 7.2. Approximately 35% experienced financial difficulties paying medical bills, including 28% who were currently paying off medical debts. Almost 14% of the respondents reported delayed/missed necessary medical treatments. In addition to direct effects, predisposing, enabling, and need factors affected access to care indirectly via financial hardship, although significant moderated mediation was found by chronic health status. However, different from the Andersen's behavioral model of health service utilization, the effect of financial hardship due to medical bills as a barrier to the timely use of necessary health services was not smaller among adults with chronic health conditions. Policy alternatives should be explored to provide affordable financing programs and adequate safety net health services to reduce the financial burden of health care for those who are financially vulnerable, especially those suffering from chronic health conditions.