Sleep disturbance is common in patients with advanced cancer, and their family carers also may suffer from sleep problems. The aims of this study were to determine the prevalence of sleep-wake disturbances in patients with advanced cancer and their carers, to monitor the amount of daytime spent in activity and rest, and to examine the relationship between sleep, physical, and psychological symptoms. This was a prospective, descriptive observational study in patients with advanced incurable cancer and their carers attending a regional cancer center, using subjective (Short Form-36, Epworth Sleepiness Score, Hospital Anxiety and Depression Scale, Memorial Symptom Assessment Scale, and sleep history and diary) and objective (Actiwatch) assessments over a seven-day period. Sixty patients with advanced cancer and their family carers completed the study. Poor sleep was a frequent complaint: 47% of the patients and 42% of the carers reported that they did not sleep well, yet patients reported sleeping an average of 8.2 hours and carers 7.8 hours per night. The objective assessments revealed that although sleep efficiency (SE) was greater than 90% for most patients and carers, sleep fragmentation was high in both groups. Patients and carers who complained of poor sleep were significantly more anxious (P<0.001 and <0.05) compared with patients and carers who reported sleeping well. Patients who complained of poor sleep had significantly more pain (P<0.05). These results show that a substantial proportion of advanced cancer patients and their carers complained of poor sleep despite reporting "normal" duration of sleep. Objective measurements using Actiwatch revealed good SE but high levels of sleep fragmentation and movement, suggesting that sleep quality may be disturbed. Further work is required to investigate sleep quality and the consequences of poor sleep. In the meantime, health care professionals need to routinely inquire about sleep and consider possible reversible underlying factors, such as pain and anxiety, for those who report sleep disturbance.