The maximal oxygen uptake (VO(2) max) is a standard tool for preoperative counseling of candidates for lung and heart transplantations, as well as an optional measurement to assess liver or renal transplant patients. Also, it provides an objective tool of the functional capacity of posttransplant patients. Exercise limitation and loss of aerobic capacity are common among patients with end-stage liver disease. The functional capacity of these subjects is decreased, as estimated by measuring the VO(2) max in a cardiopulmonary exercise test (CPET). After transplantation improvement is expected in physical capacity. We sought to describe the influence of orthotopic liver transplantation (OLT) on the physical fitness of the recipient at 3 and 12 months after transplantation. Since CPET is an objective test, it is an important tool for clinicians to evaluate patients' functional capacity before and after OLT.