Objectives. We compared differences in mental health needs and provision of mental health services among residents of Santiago, Chile, with private and public health insurance coverage. Methods. We conducted a cross-sectional survey of a random sample of adults. Presence of mental disorders and use of health care services were assessed via structured interviews. Individuals were classified as having public, private, or no health insurance coverage. Results. Among individuals with mental disorders, only 20% (95% confidence interval [CI] = 16%, 24%) had consulted a professional about these problems. A clear mismatch was found between need and provision of services. Participants with public insurance coverage exhibited the highest prevalence of mental disorders but the lowest rates of consultation; participants with private coverage exhibited exactly the opposite pattern. After adjustment for age, income, and severity of symptoms, private insurance coverage (odds ratio [OR] = 2.72; 95% CI = 11.6, 4.6) and higher disability level (OR = 1.27, 95% CI = 1.1, 1.5) were the only factors associated with increased frequency of mental health consultation. Conclusions. The health reforms that have encouraged the growth of the private health sector in Chile also have increased risk segmentation within the health system, accentuating inequalities in health care provision.