This article presents research on robot therapy for elderly residents in a care house. Experiments were conducted from June 2005, lasting more than 2 months. Two therapeutic baby seal robots were introduced to the residents, and activated for over 9 hours daily. To investigate the psychological and social effects of the robots, the residents’ activities in public areas were recorded using video cameras, during the daytime (8:30–18:00) for over 2 months. In addition, urinalysis of the residents was performed for 17-ketosteroid sulfate and 17-hydroxycorticosteroid. Results of the video analysis indicated that social interaction increased through interaction with the seal robots. Results of the urine tests showed that the reactions of the subjects’ vital organs to stress improved after the introduction of the robots