Although customer complaining behavior has been studied in the traditional market place, little research has been done on handling online customer complaints. This study is aimed at investigating the effects of post-purchase evaluation factors on propensity to complain in the onhne versus offline-shopping environment. Post-purchase evaluation factors from previous studies such as the degree of dissatisfaction, importance of the purchase, perceived benefits from complaining, personal characteristics, and situational infiuences have been examined. A survey was conducted and its results reveal the different impacts of post-purchase evaluation factors on propensity to complain in the online versus offline shopping environments. Further, the results suggest how propensity to complain infiuence the customer's repeat purchase intention both in online and offline shopping.