Background Certain occupational groups have formerly been identified as having higher risks of suffering from chronic Inflammatory bowel diseases. These were evaluated in an independent data set. Methods A cohort, comprising all 2 273 872 male and female Danes aged 20–59 years on 1 January 1981, and a cohort of 2 387 620 men and women 1 January 1986 were followed up for hospitallzations due to chronic inflammatory bowel disease until 31 December 1990. Results From 1981 to 1990 6296 first time admissions occurred. The incidence increased from 1981–1985 to 1986–1990. Of 363 male and 213 female occupational groups eight and five groups respectively had statistically significant raised standardized hospitalization ratios. Among 15 groups previously found to have significant odds ratios only female office staff and health occupations were found to have statistically significant raised standardized hospitalization ratios. Ratios for occupational groups with non-daytime work were not statistically significant. Compared to occupations without sedentary work occupations with predominantly sedentary work had a standardized hospitalization ratio of 125 (95% confidence interval 95% CI: 116.9–133.1). Self-employed had low hospitalization rates, while ‘other salaried staff’ and ‘not economically active’ had high rates. Conclusions We found no consistent pattern of occupations at increased risk except that sedentary work may increase the risk of attracting chronic inflammatory bowel disease.