Insomnia is a common sleep disorder with devastating socioeconomic consequences. Even though there are pharmacological and behavioral treatments for insomnia, most of the patients are treated with medications. However, the long-term use of medications to treat insomnia is questioned and has potential side effects. More and more Americans are seeking complementary/alternative treatments for many conditions including insomnia and there are anecdotal reports/case series of use of acupuncture in treating insomnia. To examine critically the role of acupuncture in treatment of insomnia, we performed a systematic review of published literature. Among the selected studies for review many were clinical case series and few open or randomized clinical trails. Even though several of these studies did not clarify the nature of insomnia (primary vs. secondary), it seemed that many of the subjects enrolled in these studies had co-morbid other psychiatric (depression or anxiety disorders) and/or medical conditions (Hemodialysis, Stroke, Pregnancy). Except for few, several of these studies had methodological limitations. Despite the limitations of the reviewed studies, all of them consistently indicate significant improvement in insomnia with acupuncture. Further methodologically strong, randomized controlled studies with large sample size are needed to assess the usefulness of acupuncture in treatment of insomnia and explore the possible mechanisms underlying the effects of acupuncture on sleep and sleep disorders.