BACKGROUND Maturation of sleep in children may be influenced by sociofamilial factors. Data concerning sleep schedule are still lacking in children at the onset of their school attendance. METHODS Eighty-five children aged 6 to 7 years were asked to complete a questionnaire with the help of their teachers. The questionnaire was completed each day for 9 consecutive days in January, March and May. It took into account bed time, awakening time and intervening factors. RESULTS Analysis of sleep schedule showed shortening of the mean sleep duration from January to May. The children did not sleep long enough and their sleep length varied from day to day depending on bed time. Variability of bed time was much larger in the evening before a day without school than before a school day. CONCLUSIONS This study shows the importance of subjective and physical comfort on sleep qualify. The role of social and familial attitudes toward regularity of sleep schedule emphasizes the need for better parental information.