Although traumatic events are presumed to cause sleep disturbances, particularly insomnia, sleep in populations subjected to forced displacement has received little attention. The present study examined the prevalence of insomnia and associated factors in internally displaced persons (IDPs) from Abkhazia 15 years after displacement to Tbilisi. Detailed subjective information about sleep–wake habits, sleep-related and stress-related parameters were obtained from 87 IDPs categorized into good sleepers and insomniacs. The Insomnia Severity Index, Perceived Stress Scale and Beck Depression Inventory were administered. The incidence of insomnia was 41.4%. The majority of insomniacs strongly believed that war-related stress accounted for the onset of their insomnia. Stepwise regression (95% confidence interval) revealed four variables significantly associated with insomnia status: self-estimated influence of war related stress (odds ratio (OR) = 2.51), frequency of nightmares (OR = 1.6), Perceived Stress Scale score (OR = 1.14) and Beck Depression Inventory score (OR = 1.12). Insomnia in IDPs was strongly related to war-associated remembered stress. ‛Over thinking’ about major stress exposure enhanced IDPs' vulnerability to insomnia. These findings have implications for the management of insomnia and associated impairment of daytime functioning in IDPs. Copyright © 2011 John Wiley & Sons, Ltd.