Infant sleep is a major source of distress in many families. The purpose of this study was to assess infant sleep and parental sleep-related cognitions about infant sleep in clinical and control samples. The clinical sample consisted of 48 infants referred to a sleep clinic because of night-wakings problems. The control sample included 48 infants with no parental complaints about sleep difficulties. Sleep of all participating infants was monitored for 1 week with actigraphs and parental daily logs. Parents completed 2 questionnaires testing their cognitions about infant sleep. As expected, significant group differences were found with regard to the sleep-quality measures and parental cognitions. Parental cognitions about difficulties in limit setting were associated with poorer sleep quality. Significant differences were found between fathers and mothers on the cognitions scales. The results highlight the links between parental cognitions and infant sleep and the unique perspective of each parent in this area.