OBJECTIVE To evaluate the effect of University of Wisconsin (UW) solution on composite facial flaps in dogs to offer a preservation time limit for clinical application. METHODS The experiment included 2 parts. In part 1, 32 half facial flaps were cold stored for 12, 24, 36, and 48 hours in UW solution (experimental group) or normal saline (control group). In part 2, 8 flaps that had been cold stored in UW solution for 24 (group A, n = 3), 36 (group B, n = 3), and 48(group C, n = 2) hours were autotransplanted. RESULTS After preservation in part 1, the viability of each tissue type (skin, mucosa, muscle, blood vessel, nerve, and gland) in the experimental groups was better than that in the control group. Muscle viability decreased more quickly than did the viability of other tissue. In the experimental groups, the viability of all tissue preserved for 12 and 24 hours was better than that of tissue preserved for 36 and 48 hours. After 48 hours of preservation, tissue had good structure and integrity in the experimental group but showed degeneration in the control group. In part 2, the flap survival percentages were 100%, 100%, and 99.7% in group A; 93.2%, 95.7%, and 94.1% in group B; and 87.2% and 86.1% in group C. Six months after surgery, the dogs in group A showed contraction potential and corneal reflex. CONCLUSIONS Twenty-four hours could be considered a reference time for clinical application of UW solution flap preservation.