A case control study was performed to identify risk factors for colic caused by simple colonic obstruction and distension (SCOD) in the horse. Case horses were recruited from 2 veterinary school clinics. Control horses were population based and matched by time of year. A number of risk factors were considered in the following areas: general carer and premises information; exercise information; husbandry information (housing- and pasture-related); feeding information; breeding information; behavioural information; travel information; preventive medicine information and pevious medical information. All variables with a P value of <0.2 in the univariable analysis were considered for possible inclusion in a multivariable model. A final model, produced by a forward stepwise method, identified crib-biting or windsucking, an increasing number of hours spent in a stable, a recent change in a regular exercise programme, the absence of administration of an ivermectin or moxidectin anthelmintic in the previous 12 months and a history of travel in the previous 24 h as associated with a significantly increased risk of SCOD. An alternative final model, produced by a backwards elimination method, identified the same variables as the forward model with, in addition, a history of residing on the current establishment for less than 6 months, a history of a previous colic episode and the fewer times per year the teeth were checked/treated as associated with a significantly increased risk of SCOD. Three of the risk factors in this model were associated with a large increase in risk: stabling for 24 h/day, crib-biting/windsucking and travel in the previous 24 h.