The prevalence of insomnia in the HIV-seropositive population is estimated to be 29-97%, far greater than the 10% general population prevalence. We carried out a systematic review to assess whether the prevalence of insomnia is indeed higher in HIV-seropositive patients and to better understand the correlates of insomnia in order to attempt to explain the dramatically higher prevalence. Nineteen studies met our search criteria and were included in this review. We found that prior studies estimated the rate of disturbed sleep, but not a single study estimated the prevalence of insomnia using insomnia diagnostic criteria, which require that sleep disturbance occur frequently, persistently, and in association with impairment in quality of life or daytime function. We also found that in addition to correlates of sleep disturbance seen in the general population, there are also correlates specific to the HIV-seropositive population: stage and duration of HIV infection, and cognitive impairment. The most important conclusion of this review is that the prevalence of insomnia which meets diagnostic criteria has yet to be estimated in populations of HIV-seropositive patients and studies are needed to estimate this prevalence rate. The rate of sleep disturbance identified in HIV-infected patients (29-97%) should not be compared against the approximately 10% prevalence of clinically significant insomnia in the general population, which would suggest that HIV infection is associated with an alarming increase in sleep problems. Instead, this rate is best compared with the rate of sleep disturbance in the general population, which is roughly 33%.