The intracellular distribution of the transformation-associated cellular protein p53 was studied by indirect immunofluorescence in a series of adenovirus-transformed rodent cells. In most adenovirus 2 or 5 (group C) transformed cell lines p53 was detected in discrete areas in nuclei and in all cell lines p53 was also present in a perinuclear structure. The adenovirus 2 or 5 E1B-58 kD protein, previously found to form molecular complexes with p53 in group C transformed cells, colocalized with p53 in both intracellular locations. Further studies on the region of the cell corresponding to the perinuclear body containing p53 showed that it frequently included the centrosomes of the transformed cell. The intranuclear p53 was released by mild DNAase I digestion.