We followed up on 134 women who had been diagnosed with cervical dysplasia to examine the relationship of dietary and serum vitamin A to subsequent cervical cancer. The subjects were women attending the Papanicolaou test screening for residents in Miyagi, Japan and histologically diagnosed as having cervical dysplasia between October 1987 and September 1988. Personal interviews were carried out, and blood samples were taken on the date of diagnosis of cervical dysplasia. The subjects were followed-up with cervical smear and colposcopy at about 3-month intervals from the date of interview until the end of February 1995. During the follow-up, 8 women (5.9%) developed cancer in situ or invasive cervical cancer and 106 (79.1%) reverted to normal. The rate of progression of the cancer in situ or invasive cervical cancer was 4.5 times higher in women with lower serum retinol levels than those with higher serum retinol levels (p = 0.08). The results suggest an association of low serum retinol level with development of cervical cancer.