IMPORTANCE When clinicians work with symptoms of infection, they can put patients and colleagues at risk. Little is known about the reasons why attending physicians and advanced practice clinicians (APCs) work while sick.OBJECTIVE To identify a comprehensive understanding of the reasons why attending physicians and APCs work while sick. DESIGN, SETTING, AND PARTICIPANTS We performed a mixed-methods analysis of a cross-sectional, anonymous survey administered from January 15 through March 20, 2014, in a large children's hospital in Philadelphia, Pennsylvania. Data were analyzed from April 1 through June 1, 2014. The survey was administered to 459 attending physicians and 470 APCs, including certified registered nurse practitioners, physician assistants, clinical nurse specialists, certified registered nurse anesthetists, and certified nurse midwives. MAIN OUTCOMES AND MEASURES Self-reported frequency of working while experiencing symptoms of infection, perceived importance of various factors that encourage working while sick, and free-text comments written in response to open-ended questions. RESULTS Of those surveyed, we received responses from 280 attending physicians (61.0%) and 256 APCs (54.5%). Most of the respondents (504 [95.3%]) believed that working while sick put patients at risk. Despite this belief, 446 respondents (83.1%) reported working sick at least 1 time in the past year, and 50 (9.3%) reported working while sick at least 5 times. Respondents would work with significant symptoms, including diarrhea (161 [30.0%]), fever (86 [16.0%]), and acute onset of significant respiratory symptoms (299 [55.6%]). Physicians were more likely to report working with each of these symptoms than APCs (109 [38.9%] vs 51 [19.9%], 61 [21.8%] vs 25 [9.8%], and 168 [60.0%] vs 130 [50.8%], respectively [P < .05]). Reasons deemed important in deciding to work while sick included not wanting to let colleagues down (521 [98.7%]), staffing concerns (505 [94.9%]), not wanting to let patients down (494 [92.5%]), fear of ostracism by colleagues (342 [64.0%]), and concern about continuity of care (337 [63.8%]). Systematic qualitative analysis of free-text comments from 316 respondents revealed additional reasons why attending physicians and APCs work while sick, including extreme difficulty finding coverage (205 [64.9%]), a strong cultural norm to come to work unless remarkably ill (193 [61.1%]), and ambiguity about what constitutes "too sick to work" (180 [57.0%]). CONCLUSIONS AND RELEVANCE Attending physicians and APCs frequently work while sick despite recognizing that this choice puts patients at risk. The decision to work sick is shaped by systems-level and sociocultural factors. Multimodal interventions are needed to reduce the frequency of this behavior.