An important element in retailing is the use of impulse purchases; generally small items that are bought by consumers on the spur of the moment. By some estimates, impulse purchases make up approximately 50 percent of all spending by consumers. While impulse purchases have been studied in the brick-and-mortar retail environment, they have not been researched in the online retail environment. With e-commerce growing rapidly and approaching 20billionperyearintheCanadianandUSmarkets,thisisanimportantunexploredarea.UsingrealpurchasingbehaviourfromvisitorstotheReunionwebsiteofHuntsvilleHighSchoolinOntarioCanada,Iexploredfactorsthatinfluencethelikelihoodofanimpulsepurchaseinanonlineretailenvironment.Consistentwithdiminishingsensitivity(mentalaccountingandthepsychophysicsofpricing),theresultsindicatethatthelikelihoodofaconsumerpurchasingtheimpulseitemincreaseswiththetotalamountspentonotheritems.Theresultsalsoshowthatpresentingtheofferinapopupisamoreeffectivelocationandpresentationmodethanembeddingtheofferintothecheckoutpageandincreasesthelikelihoodoftheconsumermakinganimpulsepurchase.Inaddition,theresultsconfirmthatprovidingareasontopurchasebylinkinga1 donation for a charity to the impulse item increases the frequency of the impulse purchase