Objective. Uterus transplantation (UTx) has been proposed as a method to treat women with absolute uterine factor infertility. The aim of this study was to evaluate the viability of the transplanted rat uterus after exposure to long warm ischemic times, in order to mimic a time frame likely to occur in a human situation during complicated pelvic vascular anastomosis surgery. Design. Experimental study. Setting. Obstetrics and Gynecology Department. Population. Female Lewis rats. Methods. Pseudopregnant rats were randomly allocated into two intervention groups, a standardized syngeneic UTx procedure (control; n = 10) and a modified UTx protocol with a four hour extended period of warm ischemia (n = 10). Main outcome measures. Scoring systems of gross morphology and histology at three and six days after transplantation. Results. Evident signs of necrosis were seen in five of 10 animals in the warm ischemia group compared with only one of 10 in the control group. Overall, uterine grafts from the warm ischemia group obtained poorer gross morphology scores. Histological findings correlated with the surgical findings at inspections three and six days after surgery. Conclusions. An extended warm ischemic time has detrimental effects on the survival of the uterus after transplantation.