This is the first follow-up study on the association between cannabis withdrawal symptoms and risk of relapse to cannabis use. Withdrawal symptoms were assessed in 36 subjects seeking treatment for cannabis dependence. All were free of other substance use or alcohol abuse in the month before abstinence from cannabis. Follow-up was performed 26±4 months later, and at this point, the withdrawal symptoms were re-assessed. The following symptoms were significantly elevated after abstinence compared with follow-up: irritability, anger, depression, restlessness, craving, sleep problems, strange dreams, increased appetite, violent outbursts, sweating, hot flashes, chills, and shakiness. This offers further validation of a cannabis withdrawal syndrome. Average withdrawal scores at baseline did not differ with gender, age, treatment type, extent of cannabis use, or a lifetime history of anxiety or affective disorders. Withdrawal scores at baseline did not predict relapse during follow-up.