Background: A specialties' lifestyle is known to be important for specialty selection, but how medical students define this concept is unknown. Purpose: The aim of this article is to determine how 4th-year medical students perceive lifestyle of specialties. Methods: All 4th-year U.S. medical students graduating in 2009 with a military service obligation were invited to participate in an electronic survey. Responses to an open-ended question, "When someone says 'That specialty has a good lifestyle,' what does that mean to you?" were classified into themes by a consensus of the authors and then compared to the students' selected specialty. Results: Response rate for the questionnaire was 46% (369 of 797). Four themes describing lifestyle emerged: "schedule control" (67% of students), "off time" (53%), "financial aspects" (48%), and "work life" (26%). Conclusions: Medical students' definition of a "good lifestyle" includes four themes, which should be used in future research of the lifestyle factor of specialty selection.