Background: T lymphocytes are an essential component of allograft rejection and tolerance. The aim of the present study was to analyze and compare the characteristics of T cell subsets in patients who underwent deceased donor liver transplantation (DDLT) versus living donor liver transplantation (LDLT). Material/Methods: Between April 2013 and June 2014, 64 patients underwent adult liver transplantation. The distribution of peripheral blood T lymphocyte subsets before transplantation and at 4, 8, 12, and 24 weeks post-transplantation were monitored serially. Results: In the serial peripheral blood samples, the absolute CD3+ T cell counts in the LDLT group were higher than those in the DDLT group (p=0.037). The CD4+, CD8+, CD4/CD8, V delta 1, V delta 2, and gamma delta T cell counts did not change significantly over time in either group. The V delta 1/V delta 2 ratio was higher in patients with cytomegalovirus (CMV) infection than in patients without CMV infection (0.12 versus 0.26; p=0.033). The median absolute CD3+ and CD8+ T cell counts in patients with biopsy-proven acute rejection (BPAR) were 884 (range, 305-1,320) and 316 (range, 271-1,077), respectively, whereas they were 320 (range, 8-1,167) and 257 (range, 58-1,472) in patients without BPAR. The absolute CD3+ and CD8+ T cell counts were higher in patients with BPAR than in patients without BPAR (p=0.007 and p=0.039, respectively). Conclusions: With the exception of CD3+ T cells, T cell populations did not differ significantly between patients who received DDLT versus LDLT. In liver transplantation patients, CMV infection and BPAR were closely associated with T cell population changes.