Sleep patterns of 50 infants (aged 9-24 months) with sleep disturbances were studied by using an activity monitor (actigraph) and parental reports during the baseline and intervention periods. Two behavioral intervention methods were used to treat the multiple or prolonged night-waking problems. Infant sleep significantly improved during the period of intervention as measured by both actigraphic and parental monitoring. The discrepancy between parental and actigraphic measures increased over time, as did the number of omitted items from the parental daily logs. The results highlight some of the advantages as well as some of the limitations of actigraphic and parental monitoring of infant sleep, and they suggest that the two methods may have complementary roles in assessing intervention efficacy in this field.