The growth of online social networks around the world has created a new place of interactionand communication among people. Individuals can share their knowledge,opinions, and experiences with one other due to the online social networks providedfeatures and may have an impact on people’s behavior in terms of communicationand purchasing.The purpose of this study is to examine the impact of online social networks (Facebook)on consumers’ purchasing decision process in food retailer shops. More precisely,the authors are trying to find which steps do online social networks influenceconsumers’ purchasing decision when it comes to food retailers; and why are thesesteps influenced by online social networks.A theoretical framework based on previous study showed there is a gap regardingonline social networks on consumers’ purchasing decision behavior in the study offood retailers. In order to have a further understanding on consumers’ purchasing behaviorregarding food retailers on online social networks, face-to-face and telephonein-depth interviews with eleven interviewees are conducted during the study. Theempirical data are presented under the research questions, and sorted by the type ofinformation. The author analyze empirical finding by linking the finding with theoriesfrom theoretical framework. The authors found out that online social networksimpact every step of consumers’ purchasing decision process to different extent regardingfood retailer shops. The reasons are mainly because Facebook’s featuresbring convenience to people, consumers spend more time on it, and Facebook’s featuresallow consumers to interact with supermarkets and other consumers and seecomments from other consumers on supermarkets’ Facebook pages.