The expression of cyclin E, one of the important positive cell cycle regulators, was examined immunohistochemically in gallbladder carcinomas. Cyclin E gene product was detected in 58 (49%) out of 118 cases. The degree of cyclin E expression was not associated with any clinicopathological factor including histology, the depth of tumor invasion, tumor stage and patient prognosis. Cyclin E expression was not correlated with that of p53 protein statistically, whereas it was correlated with the proliferative activity of the tumor cells by PCNA (p<0.05). These results suggested that cyclin E expression may confer progression of gallbladder carcinomas.