This article presents characteristics of an obsessive-compulsive disorder, its behavioural and cognitive models and therapeutic methods developed on the basis of these models. Behavioural models based on Mowrer’s two-stage theory, according to which the fear of a certain stimulus is acquired through classical conditioning and maintained in the mechanism of instrumental conditioning, have paved the way to an exposure therapy. On the other hand, cognitive therapy with patients is based on such cognitive models which assume that the underlying causes of the disorder are dysfunctional beliefs connected with exaggerated responsibility (Salkovskis, 1985, 1989), the thought–action fusion (Rachman, 1993), unrealistic cognitive appraisals of a threat (McFall and Wollersheim, 1979) or metacognitive beliefs of thought control (Clark and Purdon, 1993, 1999; Wells and Matthews, 1994). The cognitive interventions are introduced in order to help patients cope with cognitive distortions and dysfunctional beliefs which are characteristic to this disorder. Research confirm high effectiveness of behavioural therapy in the treatment of the obsessive-compulsive disorder. Exposure and ritual or response prevention treatment is thought to be a necessary element to achieve effective treatment of the obsessive-compulsive disorder. Unfortunately, research shows that 20–30% of obsessive-compulsive disorder patients do not agree to exposure and ritual or response prevention, or resign from it. In such cases, patients are proposed to enrich behavioural therapies with cognitive elements. Numerous case descriptions and research analyses confirmed the decrease of obsessive-compulsive disorder symptoms upon the introduction of cognitive restructuring into the exposure and ritual or response prevention. The article sets to present the effectiveness of the cognitive-behavioural therapy and its individual techniques in the obsessive-compulsive disorder treatment.