Background There are limited data on population-wide assessment of cost in Crohns disease (CD) and ulcerative colitis (UC). Aim To estimate the societal cost of actively treated CD and UC in Sweden. Methods We identified 10 117 prevalent CD and 19 762 prevalent UC patients, aged >= 18 years on 1 January 2014 and 4028 adult incident CD cases and 8659 adult incident UC cases (2010-2013) from Swedish Patient Register. Each case was matched to five population comparators. Healthcare costs were calculated from medications, outpatient visits, hospitalisations and surgery. Cost of productivity losses was derived from disability pension and sick leave. Results The mean annual societal costs per working-age patient (18-64 years) with CD and UC were $22 813 (vs $7533 per comparator) and $14 136 (vs $7351 per comparator) respectively. In patients aged >= 65 years, the mean annual costs of CD and UC were $9726 and $8072 vs $3875 and $4016 per comparator respectively. The majority of cost for both CD (56%) and UC (59%) patients originated from productivity losses. Higher societal cost of working-age CD patients as compared to UC patients was related to greater utilisation of anti-TNF (22.2% vs 7.4%) and increased annual disability pension (44 days vs 25 days). Among incident CD and UC patients, the mean total cost over the first year per patient was over three times higher than comparators. Conclusion In Sweden, the societal cost of incident and prevalent CD and UC patients was consistently two to three times higher than the general population.