The laminariaceous species Saccharina sculpera has been known to distribute in southwestern Hokkaido, Japan and in south Sakhalin, Russia. However, the previous information of its distribution in Sakhalin were based on old literatures, so we conducted a survey in June 2008 to make clear the present distribution of S. sculpera in south Sakhalin. We recognized populations of S. sculpera around the edge of the Krilion Peninsula where it grew at the mean depth of 10.7 m, but could not find around Kholmsk where S. sculpera distribution was reported in literatures during 1960's. Disappearance of its populations around Kholmsk in the past 50 years awakes us to the necessity of conservation on existing natural resources. The high genetic homology was confirmed by sequencing comparison on ITSs and RuBisCo spacer between plants sampled in the present study and S. sculpera sampled at Hakodate, Hokkaido, so it was proved that the plants in south Sakhalin were surely S. sculpera.