Most trauma services throughout the country are staffed on a fixed-call rotational basis. Staff is deployed in a linear fashion when trauma often occurs in a skewed sporadic fashion resulting in large fluctuations in volume, injury severity, and mechanism of injury. Medical error and increased mortality have been associated with certain admission times. We reviewed 8015 consecutive major trauma admissions over a 3-year period. When reviewing aggregate data we found a significant difference in mortality between patients admitted during the day (7:00 AM to 6:59 PM) compared with those admitted at night (7:00 PM to 6:59 AM) (10.1% vs 13.1%, P < 0.01). On further analysis the two populations were found to be significantly different in volume, Injury Severity Score (ISS), and mechanism of injury. More patients were admitted at night and on weekends. They had a higher ISS, higher frequency of penetrating trauma, and a higher likelihood of undergoing operative intervention. Multiple subset analyses were performed stratifying for ISS, time of admission, day of admission, and mechanism of injury using mortality rate as the end point. Six comparisons were performed: 1) morning versus night admission; 2) weekday versus weekend admission; 3) least busy day (Tuesday) versus busiest day (Sunday) admission; 4) weeknight versus weekend night admission; 5) in cases of penetrating trauma, morning versus night admission; and 6) in cases of blunt trauma, morning versus night admission. None of the six comparisons showed a significant difference in mortality. There was no significant difference in ISS-matched mortality related to fixed trauma call staffing.