Acute complications commonly occur during routine hemodialysistreatments, include( hypotensive episodes, cramps, nausea,………). . Onlinehaemodiafiltration (HDF) has been reported to reduce the frequencyof intradialytic acute complications. Methodes: This study included 16children 4-16 years old CKD patients on regular hemodialysis in CPNT(at Abou Elrish Children Hospital, Cairo University). We have followedup the children for three consecutive months, then. The same group wasshifted to ol- HDF and was followed up for other three months. Wemeasured mean blood pressure, average weight gain in between dialysissessions and incidence rates of acute complications, HB, HCT, Ca, P andBUN before and after sessions before and after the study.Results: Therewas significant change in post-treatment mean arterial blood pressure inthe HDF group during the 3 months of the study (post-treatment(ol-HDF) 85.34± 4.96 mm Hg vs. 93.37±7.69 on HD) (p value =0.003).There was significant decrease in the incidence of intradialytichypotensive episodes and its related symptoms among study group onHDF was 3.062±1.81 (range 0 to6) as compared to HD was 5.375±2.96 (range 0 to 10) (P value =0.001). Conclusion: In this study,ol- HDFreduced the frequency of most of intradialytic acute complicationscompared to HD .