Presented is a rare case of nonfamilial, hormonally nonfunctional adrenocortical carcinoma with synchronous bilateral adrenal involvement. We investigated adrenal and metastatic tumors for loss of heterozygosity affecting four genetic loci containing the tumor suppressor genes p53, RB, DCC, and APC, using polymerase chain reaction and restriction fragment length polymorphism assay. Allelic losses at the p53 and RB loci were detected in all tumor samples, suggesting that the p53 and RB genes are involved in the tumorigenesis of adrenocortical carcinoma.