A 52-year-old man undergoing continuous ambulatory peritoneal dialysis presented with two consecutive episodes of peritonitis caused by unusual organisms, namely, Brevibacterium and Pantoea agglomerans. The patient was successfully treated with a 2-week course of cefazolin and ceftazidime for the Brevibacterium-associated peritonitis, and a 3-week course of gentamicin for the P. agglomerans-associated peritonitis. Although these environmental organisms are rarely responsible for human infection, the number of reported cases of human infection by these unusual organisms has increased. This report emphasizes the potential for infection by environmental organisms in patients undergoing peritoneal dialysis.