This research aims to: investigate the influence of word of mouth on purchase intention; investigate the influence of word of mouth on purchase decision; investigate the influence of purchase intention on purchase decision. The research method used in this study is explanatory research. The total sample is 116 college mobile users who adopt IM3 card at the Faculty of Administrative Science, Brawijaya University class of 2011/2012 and 2012/2113. The sampling technique used is simple random sampling with questionnaires as the instrument for collecting the data. Analysis of the data in this research uses descriptive analysis and path analysis. The results of this research show that: word of mouth has influence on purchase intention; word of mouth has influence on purchase decision; purchase intention has influence on purchase decision. Based on this research, then suggested the company PT. Indosat to take a higher concern in servicing their customer. As such, an emphatic opinion can be generated among the customer to create a positive word of mouth marketing for IM3 mobile card.