Campylobacter jejuni CG8486, which belongs to the HS4 complex, was isolated from a patient with inflammatory diarrhea in Thailand. This strain caused a diarrheal disease in ferrets comparable to that caused by C. jejuni strain 81-176, but it was much less invasive for epithelial cells in vitro than 81-176. Complete genome sequencing of CG8486 revealed a 1.65-Mb genome that was very similar to the other two published genomes of clinical isolates of C. jejuni, the genomes of 81-176 and NCTC 11168, with a limited number of CG8486-specific genes mapping outside the hypervariable carbohydrate biosynthesis loci. These data suggest that the genes required for induction of inflammatory diarrhea are among the genes shared by CG8486 and 81-176 but that either major changes in the carbohydrate loci and/or more subtle changes in other genes may modulate virulence.