BACKGROUND We assessed the alterations in portal hemodynamics associated with donor right hepatectomy and its effects on functional regeneration of the remnant liver. MATERIAL AND METHODS This prospective study included 30 adult living donors who underwent right hepatectomy in the Liver Transplantation Unit, Faculty of Medicine, Cairo University from June 2015 to October 2016. During donor surgery, portal venous pressure (PVP) was measured using an antithrombotic catheter inserted into the main portal vein, and was measured before and after clamping of the right portal vein. Postoperatively, liver function tests were done daily until normalization. The outcome measures were the time to normalization of liver function tests and effect of residual volume and steatosis on PVP. RESULTS All donors had normal PVP before clamping and changed significantly after clamping (p<0.001). After clamping, 25 donors (83%) had a PVP above 12 mmHg; i.e. had high portal pressure. The median percentage of change was 55%. There were obvious increases in liver enzymes and bilirubin after surgery, but albumin and international normalized ratio showed progressive decreases postoperatively. The percent change in PVP was positively correlated with the levels of liver enzymes, time to normalization of liver enzymes, albumin, and bilirubin, and with the degree of steatosis, bit it was negatively correlated with residual liver volume. CONCLUSIONS During living donor liver transplantation, PVP increases by over 50% after clamping of the right portal vein of the donor's liver. This increase is associated with temporary delay of normalization of liver function of the donors.