Brevibacterium casei is an extremely rare organism that can lead to peritonitis in End-stage renal disease patients of peritoneal dialysis. Out of only five overall Brevibacterium species peritonitis reported worldwide, only two of them had B. casei subspecies peritonitis detected, with both needing peritoneal dialysis catheter removal and change in dialysis modality to hemodialysis. Our patient, an elderly 63-year-old Hispanic male, was on peritoneal dialysis at home and presented with features suggestive of peritonitis. He was diagnosed subsequently with B. casei and started on broad spectrum intraperitoneal antibiotics. However, he did not need dialysis modality change and recovered fully after 3 weeks of appropriate intraperitoneal antibiotics therapy. Longer antibiotics therapy and frequent clinical follow-up plus better clinician awareness are needed to prevent this rare infection.