Peritonitis and exit-site tunnel infection are frequent causes of CAPD drop out. We studied 9 patients, 8 treated by CAPD and 1 by IPD. These patients underwent sonographic and scintigraphic study of the abdomen. All scintigraphic examinations showed a visceral uptake. In two cases, sub-clinical bowel inflammation, demonstrated by scintigraphic study, preceded a gram negative peritonitis. The scintigraphic study with radiolabelled white blood cells may be useful in identifying chronic aseptic inflammations and some bowel and exit-site conditions which are possible risk factors in some cases of peritonitis.