Transgenic mice with ectopic expression of bovine CRABP under the control of the human metallotheionein IIA promoter have shown a variety of pathological consequences. Expression of the transgene has been detected in most of the tissues examined, including heart, lung, liver, spleen, kidney, intestine, testis, and ovary, except pancreas. Two independent lines have been able to produce normal non‐transgenic F1 animals of both sexes but only female transgenic progenies. All of these F1 female transgenic animals derived from both lines are sterile, and the ovaries from these animals appear to be significantly smaller as compared to their non‐transgenic littermates. Histopathological examinations have shown no maturing follicles in these transgenic ovaries in which abnormal cells have been observed. Another independent line has generated transgenic F1 animals which have been growing retardly. These animals all have small spleen and liver and have become very sick at the age of 4 to 5 weeks. Histopathological examinations on these transgenic progenies have shown hepatocytes to be reduced in the cytoplasmic portion in which glycogen is highly depleted. The spleen is poorly developed as no well organized germinal centers can be observed in the spleen sections of these transgenic animals.