The full-length genome sequence of S. parasuis, a recently proposed new species and a close relative of Streptococcus suis, the causative agent of zoonotic diseases, was determined. S. parasuis has been detected in healthy pigs and in diseased pigs, which suggests that S. parasuis is involved in the normal microbiota of pigs and has potential pathogenicity. However, the pathogenicity of S. parasuis in pigs is unclear. Using the genome sequences, we perform comparative genomic analysis with related species such as S. suis and S. ruminantium to discuss the characteristics of the S. prasuis genome and how S. parasuis has evolved.