The diagnosis of chyloperitoneum (CP) is based on the presence of high levels of triglycerides (TGs) in the dialysate. It is a rare complication of peritoneal dialysis (PD) and even rarer in neonates. We report here the case of CP in a 1700-g male baby delivered at the 30th gestational week due to posterior urethral valve and associated oligohydramnios. On postnatal day 2, the serum creatinine (Scr) was 1.6 mg/dL, and he was anuric. PD was instituted via a Tenckhoff catheter. At the end of the second week, after the initiation of enteral feeding, the ultrafiltrate became cloudy, with a leukocyte count of 900/mm(3). A treatment regimen consisting of intraperitoneal vancomycin and ceftazidime was then started. Five days later, the fluid became milky, with a TG level of 251 mg/dL. The patient was then placed on a diet based on medium-chain triglycerides and octreotide (1 mu g/kg/h; increasing up to 2 mu g/kg/h over 15 days). Although the TG and leukocyte levels decreased, the milky appearance persisted. PD was stopped for 2 days when the Scr decreased to 1.7 mg/dL. When it was resumed, the fluid was totally clear, with a TG level of 7 mg/dL. The infant was discharged with a nightly intermittent peritoneal dialysis program and has had no recurrence. In summary, we report a preterm infant who developed CP during PD and recovered following treatment that included diet modification, octreotide, and temporary discontinuation of the PD.