The aim of this study was to investigate the use of objective and subjective sleep measures in diagnostic assessment of night-waking problems during infancy. Infant sleep-wake measures obtained from parental daily logs were compared with objective sleep measures derived from activity monitoring during a week-long period in 66 referred infants. Reported sleep measures were significantly correlated with objective sleep measures and showed a significant level of day-to-day stability. Parents were accurate reporters of sleep-schedule measures (e.g. sleep onset, r = 0.88; sleep duration, r = 0.74; p < 0.0001). However, parents were less accurate in assessing sleep quality measures, significantly overestimating the time that their infants spent in actual sleep and underestimating the number of their night-wakings (r = 0.41 and r = 0.60, respectively; P < 0.001). It is suggested that subjective and objective measures should play a complementary role in the clinical assessment of night-waking problems in early childhood.