Background: Stress levels among healthcare professionals including doctors are high compared with the general working population. General practice appears to be one of the most stressful workplaces for health service employees. Objective: To examine whether primary health care (PHC) physicians have a higher level of work stress than hospital physicians and identify the work characteristics leading to stress among physicians. Material and Methods: Cross-sectional survey of 184 general practitioners and hospital physicians at Riyadh Military Hospital in Riyadh City, Saudi Arabia. A self-administered questionnaire based on the Reeder scale to measure psychological stress level and the Health and Safety Executive's Stress Indicator Tool to explore the sources of work stress among workers was used. Data were collected over the first two weeks of May 2009. Statistical analysis used multiple linear regressions to determine predictors of work stress and work stress factors. Results: Hospital physicians reported higher Reeder scores than PHC physicians (3.28 vs 2.94, P = 0.001) and specifically in the relationships domain (1.31 vs 1.16, P = 0.004). Reeder and demand domain scores decreased with the increase in age while control and role domain scores increased with the increase in age. Gender and marital status had no statistically significant effect on stress level or work stress factors. Consultants had higher control scores compared to specialists (3.28 vs 2.97, P = 0.012). Reeder and demand scores were higher among current smokers compared with nonsmokers. Being a hospital physician, younger age, married, or a smoker was predictive of work stress among physicians. The Reeder Score was a positive predictor of demand and relationship domains, and a negative predictor for the other domains, except for the domain of change, where it had no influence. Conclusion: Work stress is higher among hospital physicians compared with PHC physicians in Riyadh. Hospital physicians are subjected to higher workloads, conflicts, and unacceptable behavior at work. Actions to reduce work stress among hospital physicians are indicated in this workplace.