In 1967 a prospective study was undertaken to assess the alleged relationship between palmar keratoses and the presence of identifiable visceral malignancies. The study group consisted of 648 essentially asymptomatic adults who underwent comprehensive examinations for cancer with special attention to the presence of palmar keratoses. Palmar keratoses were present in 24.4% of the 648, including 28.4% of men and 19.9% of women. Each of the 648 was followed for three years subsequent to examination at the Cancer Detection Center. Of the 158 in the group with keratoses, 1.9% developed identifiable visceral cancers during 3+ years of follow-up study; for 490 without keratoses, 1.8% developed cancers. The findings of this study demonstrate that asymptomatic persons with palmar keratoses are neither more nor less likely to harbor identifiable cancers than those who do not have these skin lesions.