PURPOSE: We wanted to determine whether a major improvement in access to primary care during 2000 was associated with changes in the quality of care for patients with depression. METHODS: Health plan administrative data were analyzed by multilevel regression to compare the quality of care received by patients with depression between 1999 and 2001, a time without major changes in depression care guidelines. Approximately 6,000 patients with depression who received all care in a large multispecialty medical group during any single year were subjects for this study. Thirteen different quality measures assessed process quality under the dimensions of effectiveness, timeliness, safety, and patient-centeredness. RESULTS: The largest change was a reduction in the proportion of depressed patients with no follow-up visit in primary care after starting a new antidepressant medication: from 33.0% before a change in access to care to 15.4% afterward, P =.001. During the same period, continuity of care in primary care improved (>50% of primary care visits to 1 doctor increased from 67.3% to 74.0%, P = or <.001), as did persistence of 6-month antidepressant medication (from 46.2% to 50.8%, P = or <.001). Further analyses found that the latter change was primarily associated with the change in continuity of care. Measures of subspecialty mental health care worsened during this time. CONCLUSION: Marked improvement in access to primary care for 1 year was associated with some improvement in primary care for patients with depression, but the mechanism appeared to be improved continuity. Those planning to implement advanced access to care need to do so in such a way that continuity of care is enhanced rather than harmed by the change.