N octurnists (overnight hospitalists) have been widely implemented in teaching hospitals in the United States in an effort to meet Accreditation Council for Graduate Medical Education workload standards, 1 improve overnight supervision and enhance the quality of patient care. [2][3][4][5][6][7][8] Recent data indicate that about 50% of US teaching hospitals have nocturnists. 9 Several single-centre surveys from the US suggest that nocturnist programs improve perceived quality of care, increase resident satisfaction with overnight supervision and may enhance efficiency. 3,7 However, studies have not shown reductions in hospital length of stay or rates of mortality or hospital readmission. 2 Canadian teaching hospitals have been slow to implement nocturnists. 10 Nocturnal coverage is typically provided by firstyear residents from multiple disciplines, with staff available by telephone. Nocturnists are rare, and typically all admissions are performed by residents, without caps on volumes of existing patients or new admissions. Moreover, many Canadian teaching hospitals rely on teams of residents to cover all admitted medical patients, with no caps on the number of patients per resident. In contrast, in US hospitals, first-year internal medicine residents can manage a maximum of 10 patients. 1 Limits on Canadian resident work hours are determined at the provincial level rather than nationally, as in the US. Only Quebec has stipulated a maximum shift length (16 h), with most provinces still allowing 24-hour shifts. In Europe, resident work hours are restricted to 48-hour work weeks, and 13-hour shift limits are common. 11