While mature coastal bermudagrass hay is strongly associated with ileal impaction in theSoutheastern United States, stabling on flax bedding has anecdotally been associated with thiscondition in Europe. The aim of this retrospective study was to investigate the association betweenileal impaction and the use of flax shives compared to straw as bedding in horses withcolic. Medical records of 2336 referral cases evaluated for abdominal pain between January 2008and May 2017 at the Department of Large Animal Internal Medicine, Ghent University werereviewed. Diagnosis, date of admission, age, breed, gender, body weight and stable bedding wererecorded. Conditional logistic regression analysis was used to assess the association between ilealimpaction and each individual variable. Odds ratios (OR) and 95% confidence intervals (CI)were determined. Predictors with a value of P < 0.2 were included in a multivariable Cox regressionmodel and Wald’s test was used to assess parameter estimate significance. Further, the associationbetween survival to discharge and type of bedding or type of treatment (medical versussurgical) was analyzed for horses with ileal impactions. The proportion of colic cases stabled onflax bedding at home was 11.3%. The overall prevalence of ileal impaction was 4.2%. In the flaxgroup, the prevalence of ileal impaction was 9.4% as opposed to 3.6% within the straw group.The OR of 2.8 (95% CI 1.7-4.7; P < 0.001) in the multivariable logistic regression model indicatedthat horses stabled on flax shives were approximately three times more likely to have ileal impactionsthan horses stabled on straw. There was no significant association found between ilealimpaction and the period of admission, age, gender or body weight in a multivariable logisticregression model. The odds for having ileal impaction is approximately six times (OR 6.3; 95%CI 2.4-16.4; P < 0.001) higher in draft horses than in warmbloods in the multivariable logisticregression model. No significant association was found between survival to discharge and type ofbedding or treatment. These results suggest that horses with colic that were housed on flax beddingare more likely to present ileal impactions than horses housed on straw.