The authors developed a questionnaire in Italian for investigating sleep problems in infants and toddlers. Applying the questionnaire, they conducted an exploratory investigation into the sleep behaviour of a sample of normal children during their first three years of life in order to gather preliminary data regarding the ease of use of the instrument. The questionnaire and the results of its first application (in an Italian sample of 50 healthy children aged 10-39 months) are presented. The results provide interesting information on the sleep behaviour of the young children in our sample and prompt reflections in relation to the instrument employed. The sleep behaviour questionnaire emerged, above all, as easy to use and readily comprehensible to those participating in this research study. Furthermore, it provided parents with an opportunity to reflect upon their child and his/her rhythms (in particular sleep-wake rhythms) and upon their own ability to manage these rhythms. This instrument seems, on the basis of these preliminary data, to allow the tracing of a well-defined and complete picture of the sleep behaviour of the healthy child in the first years of life.