Purpose: We established a vitamin A-deficient (VAD) model of pregnant rats to evaluate the effect of vitamin A deficiency in maternal rats on tumor formation in filial rats. Methods: Ten pregnant Wistar rats were divided into 2 groups: (1) VAD group, 6 rats were given nonvitamin A diet from 2 weeks before mating till delivery and (2) normal diet (ND) group, 4 rats were given normal diet. Twenty random neonatal rats from each group were killed on the next day of delivery. The rest neonates were given normal diet for 1 year until killed. Serum levels of vitamin A, morphology of the kidney, incidence of tumor formation, and retinoid X receptor (RXR) α messenger RNA (mRNA) expression in renal tissue were assessed for the filial rats. Results: Fifty-six and 49 neonatal rats were born for VAD group and ND group, respectively. The detection rate of nephrogenic rests (NRs) from neonates in VAD group (50%) was significantly higher than that in ND group (20%; P < .05). The incidence of nephroblastoma was 13.9% in filial rats of VAD group and 0% for ND group. The detection rate of NRs for filial rats of VAD group (30.6%) was significantly higher than that of ND group (6.9%; P < .01). The expression of RXRα mRNA in tumor tissue of the filial rats of VAD group (3.17 ± 0.15) was significantly lower than that in kidney tissue of ND group (3.58 ± 0.20; P < .01). Conclusion: Deficiency in vitamin A for pregnant rats resulted in renal dysplasia, increased NRs, and higher incidence of nephroblastoma. © 2009 Elsevier Inc. All rights reserved.