The Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (MMA) altered reimbursements for outpatient chemotherapy drugs and drug administration services. Anecdotal reports suggest that these adjustments may have negatively affected access to chemotherapy for Medicare beneficiaries. To compare patient wait times and travel distances for chemotherapy before and after the enactment of the MMA. Analysis of a nationally representative 5% sample of claims from the Centers for Medicare & Medicaid Services for the period 2003 through 2006. Patients were Medicare beneficiaries with incident breast cancer, colorectal cancer, leukemia, lung cancer, or lymphoma who received chemotherapy in inpatient hospital, institutional outpatient, or physician office settings. Days from incident diagnosis to first chemotherapy visit and distance traveled for treatment, controlling for age, sex, race/ethnicity, cancer type, geographic region, comorbid conditions, and year of diagnosis and treatment. There were 5082 incident cases of breast cancer, colorectal cancer, leukemia, lung cancer, or lymphoma in 2003; 5379 cases in 2004; 5116 cases in 2005; and 5288 cases in 2006. Approximately 70% of patients received treatment in physician office settings in each year. Although the distribution of treatment settings in 2004 and 2005 was not significantly different from 2003 (P = .24 and P = .72, respectively), there was a small but significant change from 2003 to 2006 (P = .02). The proportion of patients receiving chemotherapy in inpatient settings decreased from 10.2% in 2003 to 8.8% in 2006 (P = .03), and the proportion in institutional outpatient settings increased from 21.1% to 22.5% (P = .004). The proportion in physician offices remained at 68.7% (P = .29). The median time from diagnosis to initial chemotherapy visit was 28 days in 2003, 27 days in 2004, 29 days in 2005, and 28 days in 2006. In multivariate analyses, average wait times for chemotherapy were 1.96 days longer in 2005 than in 2003 (95% confidence interval [CI], 0.11-3.80 days; P = .04) but not significantly different in 2006 (0.88 days; 95% CI, -0.96 to 2.71 days; P = .35). Median travel distance was 7 miles (11.2 km) in 2003 and 8 miles (12.8 km) in 2004 through 2006. After adjustment, average travel distance remained slightly longer in 2004 (1.47 miles [2.35 km]; 95% CI, 0.87-2.07 miles [1.39-3.31 km]; P < .001), 2005 (1.19 miles [1.90 km]; 95% CI, 0.58-1.80 miles [0.93-2.88 km]; P < .001), and 2006 (1.30 miles [2.08 km]; 95% CI, 0.69-1.90 miles [1.10-3.04 km]; P < .001) compared with 2003. There have not been major changes in travel distance and patient wait times for chemotherapy in the Medicare population since 2003, the year before MMA-related changes in reimbursement.