Objective: Little is known about humor's use in clinical encounters, despite its many potential benefits. We aimed to describe humor during clinical encounters. Design: We analyzed 112 recorded clinical encounters. Two reviewers working independently identified instances of humor, as well as information surrounding the logistics of its use. Results: Of the 112 encounters, 66 (59%) contained 131 instances of humor. Humor was similarly frequent in primary care (36/61, 59%) and in specialty care (30/51, 59%), was more common in gender-concordant interactions (43/63, 68%), and was most common during counseling (81/112, 62%). Patients and clinicians introduced humor similarly (63 vs 66 instances). Typically, humor was about the patient's medical condition (40/131, 31%). Discussion and Conclusion: Humor is used commonly during counseling to discuss the patient's medical condition and to relate to general life events bringing warmth to the medical encounter. The timing and topic of humor and its use by all parties suggests humor plays a role in the social connection between patients and physicians and allows easier discussion of difficult topics. Further research is necessary to establish its impact on clinicians, patients, and outcomes.