Objectives: The association between asbestos exposure, measured by mean of Asbestos Cumulative Exposure Index (ACEI) and the latency period of non-malignant asbestos-related diseases (ARD) diagnosed according to the American Thoracic Society (ATS) criteria was studied. Methods: 306 exposed asbestos workers in Bari, Italy, were included in a health surveillance program. By means of a standardized questionnaire we assessed asbestos exposure through ACEI. Latency period of Asbestos Related Diseases (ARD) was also assessed. Results: We found a significant inverse correlation between latency and ACEI increasing with ARD severity. ACEI and 30-35 years of age at time of first exposure were inversely associated with the latency period. The risk of ARD increased from baseline to the 2nd follow-up and among subjects exposed for the first time before 1960. Conclusions: The most important factors that caused a reduction in the latency period were the year of first exposure and the ACEI score while smoking habits did not show to play a significant role.