Can the fundamental differences in sleep structure known to differentiate good from insomniac sleepers (e.g., sleep length, sleep onset latency [SOL], number of sleep disruptions, etc.) be identified using a behavioural sleep/wake (S/W) monitor in the home? Sixteen women (8 good and 8 insomniac sleepers) enrolled in an introductory psychology course participated in a study of S/W patterns. They used a portable version of the Ogilvie and Wilkinson (1988) behavioural response (BR) system in their homes for 4 consecutive nights. Insomniacs had greater SOLs, less efficient sleep, and tended to have a greater number of arousals as compared with good sleepers. The data indicate that the behavioural system could be used as a diagnostic tool for in-home evaluations of disorders of initiating and maintaining sleep.