A high level of chromosomal aberrations in peripheral blood lymphocytes may be an early marker of cancer risk, but data on risk of specific cancers and types of chromosomal aberrations (chromosome type and chromatid type) are limited. A total of 6,430 healthy individuals from nine laboratories in Croatia, Hungary, Lithuania, Poland, and Slovakia, included in chromosomal aberration surveys performed during 1978-2002, were followed up for cancer incidence or mortality for an average of 8.5 years; 200 cancer cases were observed. Compared with that for the low-tertile level of chromosomal aberrations, the relative risks of cancer for the medium and high tertiles were 1.78 (95% confidence interval: 1.19, 2.67) and 1.81 (95% confidence interval: 1.20, 2.73), respectively. The relative risk for chromosome-type aberrations above versus below the median was 1.50 (95% confidence interval: 1.12, 2.01), while that for chromatid-type aberrations was 0.97 (95% confidence interval: 0.72, 1.31). The analyses of risk of specific cancers were limited by small numbers, but the association was stronger for stomach cancer. This study confirms the previously reported association between level of chromosomal aberrations and cancer risk and provides novel information on the type of aberrations more strongly predictive of cancer risk and on the types of cancer more strongly predicted by chromosomal aberrations.