Sleep disorders remain largely undiagnosed in the young adult population. We worked out and used a new questionnaire to detect sleep problems in young studying adults. The self-reported sleep quality questionnaire of night and daytime habits included 27 questions. The aims of the study were the following: 1) to estimate the practical value of the questionnaire; 2) to estimate how sleep quality is associated with night and daytime habits and sleep problems; 3) to estimate the prevalence of selfreported sleep problems in Estonian young studying adults. The study group included 413 medical students of the University of Tartu, aged 19–33 years. We report the prevalence of self-reported sleep problems and correlation of sleep quality with sleep / daytime habits in Estonian students.