BACKGROUND: Shared decision making (SDM) is an important component of patient-centered care, but there is little information about its use in the primary care of depression, so we sought to study its frequency in usual care as reported by patients. METHODS: Telephone interview of 1168 depressed patients taking antidepressants in 88 Minnesota primary care clinics who were identified from pharmacy claims data soon after a prescription for an antidepressant. We measured depression severity with the 9-item Patient Health Questionnaire and used a composite measure of SDM that reflected patient involvement in treatment decisions. RESULTS: These patients reported an average score for SDM of 50.7 (standard deviation, 32.8) on a scale of 0 to 100, where higher scores equate with greater SDM. In univariate analyses, the largest differences among scores were for age (scores of 58, 53, 45, and 33 for those aged 18-34, 35-49, 50-64, and >64 years, respectively; P < .0001); duration of treatment (a score of 56.6 on treatment <6 weeks vs 45.5 if longer; P < .001); and other treatments in the past 6 months (60.5 if yes vs. 46.0 if no; P = .001). SDM was not associated with any clinic characteristics, but it was correlated with patient-reported quality of care (r = 0.48; P < .001). Multivariate analyses confirmed some of these findings while showing a more complex set of relationships. CONCLUSIONS: Older patients with depression and those who have been in treatment longer report much less SDM in their care. Improving SDM, especially for these groups, may be an important target for improving patient experience and perceived quality.