Hoarding disorder is defined as an extensive collecting and difficulty in discarding objects and items perceived by others as not useful or having low value. As a consequence it leads to numerous problems which impact not only the patient but also his/her family and other people (e.g., residents of the same block of flats). The frequency of hoarding disorder in the United States and Europe is estimated as 2–6%. In the new classifications of psychiatric disorders (DSM-5 and ICD-11), hoarding disorder is classified as a separate disorder. The scientific research shows that hoarding disorder has specific neurobiological determinants affecting mainly the cingulate gyrus, frontal cortex and insula. These regions are connected with the cerebellum with the so-called cortical-limbic loops. This suggests that the cerebellum damage may result in the development of hoarding disorder. The presented case study concerns the patient suffering from hoarding disorder with an atrophy of the cerebellar cortex and cerebellar vermis indicated by brain imaging (computer tomography and magnetic resonance imaging of the head). It was excluded that hoarding disorder may be a symptom of other psychiatric disorders. No abnormalities were found in the somatic and neurological state of the patient. On the basis of the cited research studies it may be assumed that in the case of the discussed patient, the cerebellum damage was a cause of hoarding disorder development.