Sleep disturbance in infants and young children has been treated using three strategies: psychotherapy, medication, and behavior modification. Three experiments were undertaken to treat sleep disturbance with infants and preschool children. In the first study, the effects of extinction was evaluated with 13 infants aged 6 to 18 months. In the second study, the effects of extinction plus reinforcement procedures were evaluated with 22 preschool children aged 2 to 5 years, and in the final study, the effects of reinforcement only was evaluated with 22 preschool children. A multiple baseline across subjects design was used in each experiment. Six dependent variables were monitored, including bedtime delay, sleep onset latency, night-waking, duration of each waking, parental attention, and the duration of sleep across a 24-hour-day. Parents recorded data during baseline, treatment, maintenance, and 18 month followup. Results showed 91% of infants (10/11) maintained treatment gains in the first study, 18 months after the termination of treatment. In the second study, 95% of preschool children (21/22) on the extinction plus reinforcement contingency maintained treatment gains at 18 month followup. Finally, 90% of preschool children (19/21) on the reinforcement contingency alone maintained treatment gains at 18 month followup. These studies demonstrate the efficacy of behavioral procedures in the treatment of sleep disturbance in infants and children.