We have analyzed the genetic relationships among the silkworm (Bombyx mori) strains using RAPD-PCR. A total of 137 polymorphic RAPD markers amplified from 26 different primers were used to analyze the genetic relationships among the ten silkworm strains. The genetic similarity coefficient among the ten silkworm strains were estimated using the RAPD markers by UPGMA method. Ten silkworm strains were classified into Bombyx mori consisting of the nine domesticated silkworms and Bombyx mandarina (a wild silkworm) groups at the genetic similarity coefficient of 0.496. Bombyx mori group separates further into a small clusters of four sub-group (N32, C5, C42, Zebra), 2nd sub-group (N44, KJ16, C3), 3rd sub-group (J111), and 4th sub-group (Galwon). This value was lower than any other genetic similarity coefficients among the strains tested. And Bombyx mandarina specific RAPD band patterns were observed in 19 primers from 26 polymorphic primers used. This study is the first results on the phylogenetic analysis between Bombyx mandarina (wild silkworm) and Bombyx mori (domesticated silkworm, geographical silkworms) in the molecular level using RAPD-PCR techniques.