During the last 15 years, researchers have shown that a large percentage of persons with severe or profound mental retardation or multiple handicaps have serious sleep problems. These problems can cause emotional and physical burdens for caretakers, interfere with the persons' daily learning and occupational performance, and/or exacerbate deviant behaviors. Several studies have been conducted to assess behavioral and pharmacological strategies (e.g., bedtime fading and response cost, extinction, chronotherapy, and the use of melatonin) for reducing sleep problems. Those studies are reviewed here and the effectiveness, suitability, practicality, and acceptability of the strategies are discussed. Relevant issues for future research are also examined.