© 2019 Elsevier Inc. Introduction: Residents may differentially experience high stress and poor sleep across multiple post-graduate years (PGYs), negatively affecting safety. This study characterized sleep and stress among medical and surgical residents across multiple PGYs and at specific times surrounding duty. Method: Thirty-two medical and surgical residents (Mage = 28.6 years; 56% male) across PGYs 1–5 participated in 3 appointments (immediately before duty, after duty, and on an off day) providing 96 data points. Sleep, stress, and occupational fatigue were measured by both self-report and objectively (actigraphy, salivary coritsol). Results: Residents averaged 7 h of actigraphy-estimated sleep per night but varied ±3 h day-to-day. Residents reported clinically poor sleep quality. Life stress decreased by PGY-2. All residents averaged elevated life stress values. Poor sleep quality did not differ among PGY cohorts. Discussion: Poor sleep quality is similar between early residency cohorts (PGY-1) and later residency cohorts (PGY-3+). Persistent fatigue is highest in later residency cohorts. Even the most experienced residents may struggle with persisting fatigue. Current hour policies may have shortcomings in addressing this risk.