Adverse primary care work conditions could lead to a reduction in the primary care workforce and lower-quality patient care. To assess the relationship among adverse primary care work conditions, adverse physician reactions (stress, burnout, and intent to leave), and patient care. Cross-sectional analysis. 119 ambulatory clinics in New York, New York, and in the upper Midwest. 422 family practitioners and general internists and 1795 of their adult patients with diabetes, hypertension, or heart failure. Physician perception of clinic workflow (time pressure and pace), work control, and organizational culture (assessed survey); physician satisfaction, stress, burnout, and intent to leave practice (assessed by survey); and health care quality and errors (assessed by chart audits). More than one half of the physicians (53.1%) reported time pressure during office visits, 48.1% said their work pace was chaotic, 78.4% noted low control over their work, and 26.5% reported burnout. Adverse workflow (time pressure and chaotic environments), low work control, and unfavorable organizational culture were strongly associated with low physician satisfaction, high stress, burnout, and intent to leave. Some work conditions were associated with lower quality and more errors, but findings were inconsistent across work conditions and diagnoses. No association was found between adverse physician reactions, such as stress and burnout, and care quality or errors. The analyses were cross-sectional, the measures were self-reported, and the sample contained an average of 4 patients per physician. Adverse work conditions are associated with adverse physician reactions, but no consistent associations were found between adverse work conditions and the quality of patient care, and no associations were seen between adverse physician reactions and the quality of patient care.