Insomnia is often associated with substance dependence, with evidence suggesting that individuals seeking medical attention for sleep complaints are more likely to have drug or alcohol abuse problems than the general population. Disturbed sleep is associated with the abuse of a variety of drugs, with patients dependent on nicotine, alcohol and illicit drugs all reporting poor sleep. In addition, withdrawal from nicotine, alcohol and drugs of abuse is also associated with insomnia, and this may result in an increased risk of relapse if the sleep problems remain unresolved. Although studies suggest that the majority of pharmacological and behavioural interventions for insomnia are effective in treating sleep disturbances in dependent patients undergoing short-term drug withdrawal and short and long-term alcohol withdrawal, several questions remain unanswered. For example, little is known about the risk of relapse in abstinent drug-dependent patients experiencing withdrawal-related insomnia, the effect of insomnia treatment on nicotine withdrawal, or whether insomnia interventions prevent relapse. Participants of a workshop, held at the 6th annual meeting of The International Sleep Disorders Forum: The Art of Good Sleep in 2008, evaluated whether the effective management of sleep disorders could reduce substance dependence and the risk of relapse. Following the workshop a targeted literature review was conducted addressing this question. Data from this review that either pharmacological or cognitive behavioural treatment of insomnia could reduce the risk of relapse in substance dependence were substantially lacking. Further research is therefore required to increase our understanding of the impact of insomnia on patients with substance dependence.