PIP: A reevaluation of the interpretation of findings on the number and types of genes influencing the fate of skin homografts of mice is presented. Continuing observation of 149 grafts revealed 103 successful procedures. The breakdown of successful grafts between strains is given. Except for intrastrain grafting of A/Jax mice, male-to-female grafts generally failed, whereas male-to-male, female-to-female and female-to-male grafts almost always succeeded. The disparity in results and the genetic implications of the data remain to be elucidated.