An outbreak of human parvovirus-associated erythema infectiosum in the Grampian region has enabled us to study the association between this small DNA virus and arthritis. This report deals with 42 patients with joint pains, in whom serological evidence of recent human parvovirus (HPV) infection was obtained. The clinical description of the disorder is based on 17 of the patients who were seen in the clinic and a further 13 patients for whom information was obtained by questionnaire. Detailed clinical features were not available for the remaining 12 patients. A rash was present in all 3 affected children but only 13 of the 27 adults. Viral prodromata were present in only 13 adults. 7 adults had neither rash nor viral prodromata. The arthritis was more common in adults than children and affected principally the female sex. In adults the arthritis was symmetrical, affecting the small joints of the hands, wrists, and knees most commonly. In all cases it was self-limiting, usually resolving within 4 weeks, although 1 adult had more persistent disease lasting almost 6 months. The 3 children reported in detail had less symmetrical and more persistent disease, which in 1 case has lasted over 7 months.