Reproduction and migration are energetically costly processes for adult seabirds. Therefore, efficient energy managements in late chick-rearing period are essential for the subsequent long migration. After the chick-rearing period (from early-August to mid-November), Streaked Shearwaters Calonectris leucomelas migrate from the seas around Japan to wintering areas in the tropics, 3,500-5,400 km away from their breeding colony. It might be expected that shearwaters increase their body conditions during the late chick-rearing period. In this study, we investigated whether the body condition (using scaled mass index: Peig and Green 2009) of male and female Streaked Shearwaters changed during the late chick-rearing periods (late-September, early- and late-October). Although there was no difference in the body condition of male shearwaters through the experimental period, female shearwaters in early- and late-October had higher body conditions than birds in late-September. As female Streaked Shearwaters fed chicks more frequently and left the colony for migration earlier than males. Therefore, our result suggested that female Streaked Shearwaters recovered their body conditions for the subsequent migration, which were deteriorated by relatively high reproductive effort.