Background: Few studies have examined the influence of physician workplace conditions on health care disparities. We compared 96 primary care clinics in New York, New York, and in the upper Midwest serving various proportions of minority patients to determine differences in workplace organizational characteristics. Methods: Cross-sectional data are from surveys of 96 clinic managers, 388 primary care physicians, and 1701 of their adult patients with hypertension, diabetes melli- tus, or congestive heart failure participating in the Minimizing Error, Maximizing Outcome (MEMO) study. Data from 27 clinics with at least 30% minority patients were contrasted with data from 69 clinics with less than 30% minority patients. Results: Compared with clinics serving less than 30% minority patients, clinics serving at least 30% minority patients have less access to medical supplies (2.7 vs 3.4, P<. 001), referral specialists (3.0 vs 3.5, P<. 005) on a scale of 1 (none) to 4 (great), and examination rooms per physician (2.2 vs 2.7, P=.002). Their patients are more frequently depressed (22.8% vs 12.1%), are more often covered by Medicaid (30.2% vs 11.4%), and report lower health literacy (3.7 vs 4.4) on a scale of 1 (low) to 5 (high) (P <. 001 for all). Physicians from clinics serving higher proportions of minority populations perceive their patients as frequently speaking little or no English (27.1% vs 3.4%, P=.004), having more chronic pain (24.1% vs 12.9%, P<. 001) and substance abuse problems (15.1% vs 10.1%, P =.005), and being more medically complex (53.1% vs 39.9%) and psychosocially complex (44.9% vs 28.2%) (P <. 001 for both). In regression analyses, clinics with at least 30% minority patients are more likely to have chaotic workenvironments (odds ratio, 4.0;P=.003) and to have fewer physicians reporting high work control (0.2; P=.003) or high job satisfaction (0.4; P=.01). Conclusion: Clinics serving higher proportions of minority patients have more challenging workplace and organizational characteristics.