Summary Background Barrett's oesophagus ( BO ) is a risk factor for oesophageal adenocarcinoma ( OAC ). Several studies report increasing incidences of BO with substantial variation. Aim To determine age‐ and sex‐stratified incidence rates ( IR ) of BO and OAC . Methods Cohort study using two primary care databases in the United Kingdom ( UK ) and the Netherlands ( NL ) (2000–2012). BO and OAC cases were identified using disease‐specific READ codes ( UK ) and free‐text search with manual validation ( NL ). Age‐ and sex‐specific incidence rates ( IR s) were calculated for both BO and OAC . Results From the study population of 6 885 420 subjects in the UK , we identified 12 312 incident BO and 40 (0.3%) subsequent incident OAC cases. There were 1383 incident BO , and subsequent 5 (0.4%) incident OAC cases among the 1 487 191 subjects in the NL . The IR of BO increased linearly with age: 15.6/100 000 PY s ( UK ) and 23.7/100 000 PY s ( NL ) for patients aged 40–44 years, increasing to 85.6/100 000 PY s ( UK ) and 87.0/100 000 PY s ( NL ) for 70–74 years. In both the UK and the NL , IR of BO was 2–4 times higher in males than females across all age groups. With respect to calendar time, the IR of BO increased by 35% ( UK ) and 41% ( NL ) from 2000 to 2003, after which IR s remained stable until 2012. Conclusions The incidence rates of BO in the UK and the NL increased until 2003, but levelled off thereafter. Around 0.3% of patients with BO developed OAC at least 1 year after BO diagnosis. These findings may help tailor endoscopic surveillance strategies among patients with BO .