As the analbuminemia of analbuminemic rats (NAR) is inherited as a recessive trait, the livers of F1 hybrids of Sprague-Dawley X NAR (SD X NAR) retain the capability to produce albumin. We induced albumin-negative hyperplastic nodules in the livers of NAR, isolated the nodule cells and transplanted them in the livers of SD X NAR by infusion into the mesenteric vein. When the hosts were treated with dietary 2-acetylaminofluorene plus a partial hepatectomy, numerous albumin(-) nodules of donor origin were formed within the albumin(+) livers of the hosts. This system should be useful to analyze sequential events during hepatocarcinogenesis by using a genotypic marker.