Serum albumin levels have been used as a representative marker for morbidity and mortality in the dialysis population. We evaluated the significance of various biochemical values in peritoneal dialysis (PD) patients with a history of peritonitis. In 51 patients [27 women, 24 men; mean age: 42.6 years (range: 19 - 70 years); average duration of PD: 28.26 +/- 23.1 months] with history of peritonitis, we recorded serum albumin and cholesterol levels at the beginning of PD, at the last visit (1 month) before the peritonitis episode, and at months 1, 6, and 12 after the peritonitis episode. Routine data from peritoneal equilibration tests were also obtained. Serum albumin showed a significant decline from the basal measurement at the measurements 1 month before and after the peritonitis episode (p = 0.026 and 0.025 respectively). Serum cholesterol levels and dialysate-to-plasma creatinine at hours 2 and 4 revealed no significant alterations at the same time points. The decline in serum albumin relative to the first visit (basal level) may be a factor showing the likelihood of peritonitis. A decline in serum albumin during follow-up may be an indicator for subsequent peritonitis. The absence of a similar decline in serum cholesterol levels (mimicking albumin) may rule out low dietary intake or malnutrition. Pathophysiologic explanations for these relationships are not obvious. If the leading complication of PD is peritonitis, efforts should be focused on improving the factors that influence serum albumin levels.