OBJECTIVE: This study was designed to identify predictors of duration of visits among patients diagnosed with depression in the ambulatory medical care settings. METHOD: Data from the 1999 National Ambulatory Medical Care Survey (NAMCS) were used to identify patients 10 to 75 years old with a documented diagnosis of depression (ICD-9-CM=296.2-296.36; 300.4 or 311). The unweighted sample size was 826. Multivariate linear regression was used to identify the predictors. Model variables included patients' characteristics, treatment patients received, and physicians' characteristics. RESULTS: Among the factors predictive of the duration of visits, significant factors include female patients, Medicaid patients, capitated payment, seen by other providers and receipt of psychotherapy. After controlling for other factors, physicians spend about 2.19 (95% CI: 0.03,4.35) minutes longer with female patients during the visit than male patients; physicians spend 8.13 (95% CI: 1.93, 14.32) minutes less with Medicaid patients compared with patients with private insurance; Physicians spend 8.57 (95% CI: 3.96, 13.18) minutes less with patients in a capitated visit compared to a non-capitated visit; Established patients receive 12.30 (95% CI: 5.30, 19.31) minutes less with the physician provider compared with non- established patients; Patients who receive care from other providers besides a physician such as a physician assistant, a nurse practitioner, a nurse midwife, a R.N., a L.P.N, a medical or nursing assistant spend 6.96 minutes (95% CI: 3.14, 10.77) less with the physician compared with patients who don't receive care from other providers. Patients who receive psychotherapy spend 15.60 (95% CI: 11.04, 20.06) minutes more than patients who don't receive psychotherapy. CONCLUSION: Medicaid, capitation payment and seen by other providers were three significant and negative predictors of the duration of the visit. Economic incentives may cause providers to spend less time with patients or substitute with relative cheaper health care professionals.