To estimate the incidence of, trends in and effect of change in reporting rules on occupational diseases (ODs) in the Italian agricultural sector.Over a 14-year period (2004-2017), ODs among Italian agricultural workers were diagnosed by physicians and reported to the National Institute for Insurance against Workplace Accidents and Occupational Diseases. OD was defined as a disease with a specific clinical diagnosis (International Classification of Diseases) and was predominantly caused by work-related factors. Trends in incidence and effects of changed eligibility criteria for reporting occupational musculoskeletal disorders (MSDs) and noise-induced hearing loss (NIHL) were estimated using a Poisson regression model.In 2017, the incidence of all ODs was 1295 per 100 000 agricultural workers. MSDs (961 per 100 000 workers) were the most frequently occurring ODs. MSDs and NIHL showed statistically significant increasing time trends, 26% and 7% annual increase, respectively, during the 2004-2017 period. There was no statistically significant change in the incidence of occupational respiratory, skin and cancer diseases during the 14-year period. After changes in reporting rules, the incidence of MSDs showed an immediate increased effect, with an incidence rate ratio (IRR) of 2.9 (95% CI 2.65 to 3.14) and a significant annual decreasing trend of -9% (95% CI -6% to -12%) over the years after the changed reporting rules (from 2008 to 2017), and an immediate effect on NIHL with an IRR of 1.3 (95% CI 1.13 to 1.53).In total, 1.3% of the Italian agricultural workers were diagnosed in 2017 as having an OD. Over a 14-year period, the annual incidence of ODs showed a considerable increasing trend consistent with changed eligibility reporting criteria for occupational MSDs and to a lesser extent for NIHL.