OBJECTIVES: To examine the association of self-reported health status with cost-related medication nonadherence (CRN), as well as with prescription drug out-of-pocket spending (OOP) among senior Medicare enrollees.  METHODS: We analyzed the 2008 Health and Retirement Study (HRS), a national survey of adults aged 50 or older. Self-reported health status was classified into three categories: excellent (excellent and very good), good, and poor (fair and poor) health. We estimated the association between self-report health status and 1) cost-related medication nonadherence using Logistic regression; 2) monthly out-of-pocket pharmacy spending using generalized linear model (GLM) controlling for socio-demographic characteristics and physical health conditions. All estimates were weighted to be nationally representative.  RESULTS: Among 9,090 Medicare beneficiaries aged 65 or older (mean age 74.7 years), 56.1% were female, 5.8% reported taking less medication because of cost.  Compared to those with excellent health status, beneficiaries with good health (OR=1.643, p<0.0001, 95% confidence interval [CI] 1.263-2.138) and poor health (OR=2.947, p<0.0001, 95% CI 2.264-3.834) were more likely to report cost-related medication nonadherence. The GLM regression results showed that compared to excellent health beneficiaries, the average monthly out-of-pocket pharmacy spending was $13.844 (p<0.0001, 95% CI 7.500-20.186)  higher for good health and $27.245 (p<0.0001, 95% CI 17.695-36.794) higher for poor health subjects.  CONCLUSIONS: :Drug spending is heavily concentrated among individuals 65 years or older and cost-related medication underuse among seniors has been a big public health concern, especially before the implementation of Medicare Part D in 2006. This study find that worse health status is significantly associated with increased likelihood of cost-related medication nonadherence and higher out-of-pocket expenditures for prescription drugs. Senior Medicare beneficiaries with poor health still faced higher OOP burden compared with their healthy counterparts.