The relationship between a social partner's stress status and the social buffering effect was examined in adult male Wistar rats. Fear-conditioned rats were exposed to the same context along with either a shocked or nonshocked conspecific partner. Changes in body temperature and behavioral responses were monitored in order to compare the effects of social buffering, and the Fos protein in the paraventricular nucleus was immunostained. The presence of the partner rat attenuated stress-induced hyperthermia, as well as behavioral responses and Fos expression in response to the fearful context, and nonshocked partners were more effective than shocked partners. These findings suggest that the social buffering effect depends on the stress status of the accompanying conspecific animal.