A 37-year-old-woman was admitted to our hospital because of chest bilateral reticular shadow with fever, cough, general malaise and exertional dyspnea in the summer. A diagnosis of summer-type hypersensitivity pneumonitis (SHP) was made by radiological, serological and histological examinations. Her 10-year-old daughter had chest reticular shadows and similar symptoms. These two patients were positive for serum anti-Trichosporon cutaneum (T. asahii, T. mucoides) antibodies and T. asahii was identified from cultured samples obtained from their house. They recovered spontaneously after hospitalization or isolation from the antigen. We reviewed the clinical features in sixteen families with familial SHP reported in Japan. Children aged under 15 years old accounted for 34% and there was no gender difference among patients. This finding differs from the conventionally defined features of patients with SHP. Measurements of serum KL-6, SP-D and SP-A seem to be useful for auxiliary diagnosis and monitoring the disease activity of SHP, especially in pediatric cases who cannot undergo invasive evaluation.