Background: It is imperative to understand the current work practices of hospital personnel to inform efforts and secure resources towards the improvement of hospital systems. Research examining doctors' work during night-shifts is limited. Aim: To describe and quantify the night-shift work practices of junior doctors. Methods: An observational time and motion study was conducted. Eight resident doctors in four general wards were observed for 96h during night shifts (Monday-Friday, 2200-0800). Results: Doctors spent the highest proportion (28%; 95% CI 21-35) of their time performing social/personal tasks (e.g. sleeping, eating) and indirect care (24%; 95% CI 22-25) (e.g. reviewing notes, ordering tests). Work-related discussion comprised 15% (95% CI 13-17), and most took place at the beginning of the night. Medication-related tasks consumed a small proportion of time (4%; 95% CI 3-4) but attracted a higher level of multitasking and interruptions than most other tasks. On average, 2h of every shift were spent at a computer and 1.3h with patient notes. Doctors spent 72% of the night-shift alone, multitasked 6.4% of the time and were interrupted, on average, once every 46min. Conclusions: This study provides new data about junior doctors' work at night. Relative to doctors during the day, greater proportions of time were devoted to social/personal tasks (including sleep) and indirect care, but a similar proportion to direct care. Multitasking and interruptions were minimal. Computer activities were an integral part of work. Handovers were observed at the beginning but not the completion of the night shift, which may have implications for patient safety.