The aim of this study was to explore the prevalence of parentally experienced infant sleep problems, with special interest in severe problems, in a total community sample of 2518 infants aged 6-18 mo. Correlates to severe sleep problems were sought. The families were approached using a questionnaire and 83% responded. Data from the collection procedure point to a nonselective dropout. Sixteen percent of the parents reported their children as having moderate or severe difficulties in falling asleep at night (sleep refusal, bedtime struggles) and 30% reported frequent night waking. Almost all (93%) of the parents had sought help at the Child Health Centre (CHC), but only 48% were satisfied with the support and advice they got. Severe sleep problems as defined by the ICSD (International Classification of Sleep Disorders, 1990) were found in 129 of the children (6.2%), who were studied in detail, with the rest of the population as controls. Severe sleep problems were found to be correlated with parental worries and anxiety concerning infant health (although the children were reported as being as healthy as the controls), infant feeding problems and intensive parental interventional behaviour (especially feeding) during the evening and night. A common factor of insecurity in the parental role is suggested.