A total of 112 orthotopic liver transplants with (AOLT) and without (NOLT) rearterialization were performed in 2 series using male Lewis rats as donors and recipients. In the first series, the 2-week survival rates were 5/11 (45.5%) in the NOLT group and 22/31 (71 %) in the AOLT group. The difference in survival was due to operative experience, as the NOLT transplants were performed before the AOLT transplants. In the second series, the NOLT (n = 30) and AOLT transplants (n = 40) were performed in random order. No differences in 2-week survival rates were found [NOLT, 29/30 (96.7%); AOLT, 37/40 (92.5%)]. Recovery of pre-operative body weight was, however, faster in the AOLT (7 days) than in the NOLT group (14 days). In the NOLT group, elevation of serum levels of GOT (p < 0.05 vs. AOLT at 3 days) and alkaline phosphatase (p < 0.01 vs. AOLT at 3 days and 1 week; p < 0.05 at 4 weeks) were found. We conclude from our results that in OLT without prolonged graft storage, survival is a sensitive marker of operative success only in the training phase. Once operative technique has been mastered, a success rate of greater than 90% should be achieved before inclusion of the animals in further scientific studies. As the AOLT animals recover body weight faster and have less evidence of liver injury up to 4 weeks post-transplantation, one is led to the conclusion that AOLT in the rat may be a better model for use in all liver transplantation research.