Cytologic smears of palatal mucosa were evaluated for degree of keratinization in 217 healthy men ranging in age from 30 to 74 years. Two slides were prepared for each participant, and each slide was read by two different pathologists. Three separate high-power fields were examined on each slide, and the percentage of orange-brown cells, either without nuclei or with pyknotic or fragmented nuclei, was recorded. A mean value was obtained for each participant. Each participant had an extensive medical and dental work-up as part of the Veterans Administration Longitudinal Study of Oral Health in Healthy Veterans. Nonsmokers and smokers were divided into five age groups. Smokers at all ages presented a greater degree of palatal keratinization than nonsmokers, but age differences in keratinization were not statistically significant.