Neuropsychiatric side-effects have been reported in up to 60% of patients undergoing treatment with antiviral agents [Evon et al. 2009]. Most of them (48%) were depressive disorders. More rarely, signs and symptoms associated with anxiety, sleep, memory and attention disorders were observed [Lochet et al. 2003; Ward and Curtin, 2006]. Ribavirin, an antiviral agent, has also been reported to cause some psychiatric syndromes, however it is stressed that these effects are often enhanced by the psychiatric side-effects of the other antiviral agents (such as interferon alpha) which are often used together [Reichard et al. 1997; Martin-Santos et al. 2008]. We would like to report a case of single-agent ribavirin-induced compulsive buying. The purpose of this case report is to draw attention to obsessive compulsive spectrum disorders (OCSDs) such as compulsive buying, which, although not defined as a disorder by the DSM and ICD, may cause clinically significant disability, and also to its etiology of biological and psychological explanations. A 34-year-old woman presented to our clinic with obsessive fears of becoming contaminated by microbes whenever she touches any item, continuous thoughts of having forgotten to turn the lights off and close windows and doors, uncontrolled repetitive behaviors in the form of a compulsive need to constantly check the doors or lights or continuously wash her hands. She also had sudden and intense desires to shop and purchase things needlessly. When she postponed the desire to shop, she experienced severe discomfort and restlessness. She gained relief by buying unnecessary things, hence she faced economical problems due to excessive expenditure, resulting in regret and anxiety feelings. Three weeks prior to her application, she received a prophylaxis treatment consisting of 1000 mg/day oral ribavirin applied for 7 days since she had pricked her finger with a syringe that had been used on a patient with Crimean-Congo hemorrhagic fever disease. During the medication usage she had no complaint other than a feeling of dizziness and lack of concentration. The prophylaxis treatment for Crimean-Congo hemorrhagic fever disease was completed and the disease did not appear. The aforementioned psychiatric symptoms and complaints started a week after the completion of this treatment with ribavirin. It was determined via psychiatric examination that she was in an anxious–angry mood, her thoughts included suspicion and contamination obsessions, control and washing compulsions, and intense desire to go shopping; her behavior of purchasing unnecessary things was noted and, after purchasing, she experienced thoughts of guilt. Routine hematological and biochemical parameters were normal. Tests also revealed a Beck Depression Inventory score of 6, Beck Anxiety Inventory score of 7, Yale–Brown Obsessive Compulsive Scale score of 15, Brief Symptom Inventory overall average symptom score of 0.51, obsessive–compulsive symptoms subscale score of 1.3, and interpersonal sensitivity subscale score of 0.66. The patient had received 6 months’ treatment with paroxetine 20 mg/day for the diagnosis of depressive disorder after her father’s death in 2004. She recovered after this treatment and had not had any psychiatric complaints since then. She had no other medical disease. Her aunt was receiving treatment for a diagnosis of obsessive–compulsive disorder (OCD). As a result of these signs and symptoms, cognitive–behavioral treatment was planned with this patient, diagnosed with ribavirin-induced subthreshold OCD and compulsive buying (an impulse control disorder not otherwise specified [ICD-10 F63.9]). A decrease in obsessive–compulsive complaints was seen in the second week. Behavioral recommendations were given for compulsive buying (make a list before shopping, take only enough cash for the items on the list, do not use a credit card, do not go shopping alone). After 1 month of treatment the obsessive–compulsive symptoms disappeared completely but, although at a decreased level, the patient’s complaints of compulsive buying still continued.