Background Results of peritoneal equilibration test (PET) suggest prolonged effect of polyglucose dialysis solution (PG-DS) on peritoneal permeability. Objectives An evaluation of dialysate-to-plasma ratio (D/P) of urea, D/P creatinine, and D/D0 glucose (ratio of dialysate glucose at designated dwell time to dialysate glucose at 0 dwell time), and mass transfer area coefficients (KBD) of these solutes in PET before introduction, during administration, and after discontinuation of PG-DS in patients treated with continuous ambulatory peritoneal dialysis (CAPD). Design Single-center prospective study with PG-DS; retrospective selection of the control group. Setting Peritoneal dialysis unit in a university hospital. Patients Fourteen patients (11 males; age 45.1 ± 8.5 years) treated with CAPD for 17.5 ± 9.9 months. 7.5% PG-DS was used for the overnight exchange. After discontinuation of the PG-DS, standard dialysis solutions, as previously used, were reintroduced. The control group was selected to match both CAPD duration and peritoneal permeability of the patients in the PG-DS group at the start of the study. Methods Standard PET was carried out at 1.6 ± 0.8 months before the introduction of PG-DS (study period I, n = 14), after 1.2 ± 0.6 months’ use of PG-DS (study period II, n = 14), after 4.4 ± 0.8 months’ use of PG-DS (study period III, n = 11), after 8.8 ± 2.2 months’ use of PG-DS (study period IV, n = 9), and at 2.0 ± 0.6 months after PG-DS discontinuation (study period V, n = 11). Patients in the control group underwent PET at similar time intervals (control periods I – V). Results In the PG-DS group, a tendency toward increased peritoneal permeability for urea and creatinine was shown during the consecutive study periods. D/D0 glucose was significantly higher only in the PET performed during use of PG-DS (periods II – IV) compared to results obtained in period I. In the control group, both D/P and KBD of both urea and creatinine remained unchanged, but KBD glucose was higher in the first 2 hours of the PET in control period V compared to respective values in control period III. Conclusion Changes in peritoneal permeability are observed in CAPD patients treated with PG-DS. These changes may be at least partially related to the administration of polyglucose.