Delusional parasitosis (DP), which is also known as Ekbom syndrome, is a rare delusional disorder where the patient is convinced of being infested with worms, insects, parasites or bacteria, while no objective evident exist to support this belief. Because patients believe that the disorder is due to the physical cause, they usually apply dermatologists or family practitioners for treatment at first, and referred to psychiatrists after their symptoms become more prominent. Somatic delusion is shared with one or more members of a family (folie a deux-trois) or by all members of the family (“folie a familie”) in 5-15% of DP cases. Today, second generation (atypical) anti-psychotics are used in the treatment. In this paper, a primary case of DP presenting as shared psychotic disorder (SPD) in the form of “folie a famille,” clinical picture and treatment process is presented. We used olanzapine for treatment of primary case. Her symptoms ceased within 3 months and other family members became asymptomatic without any medication. She was still asymptomatic at the end of 4 months. This case report is important in terms of showing psychosocial impact of DP and SPD comorbidity and to create awareness about this disease among health care providers.