Instant Messenger is a communication tool which allows instant real-time connection between parties through Internet Compared to the most popular Internet communication tool. email. the messenger allows people to check network presence of other parties and to connect in real time among multiple parties. Mostly due to the convenience it provides. use of instant messengers has increased tremendously not only for personal purpose but also for business purpose. However. firms are agonizing about the real impact of instant messenger usage among employees. whether the impact is positive or negative in terms of the productivity, Applying the theory of reasoned action (TRA) and technology acceptance model (TAM). this study sets UP perceived ease of use. perceived usefulness and cultural orientation of individuals as antecedents of adoption and use of the messenger application, Also. the impacts of messenger usage are measured as task productivity and intimacy among colleagues. This study presents several findings about the instant messenger, First. perceived ease of use. and usefulness play important roles in raising the adoption level of instant messenger. Also. culture propensity also maintains strong influence towards the actual usage of the messenger. Among cultural variables. innovativeness, supportiveness and outcome orientation reveal strong positive impacts on adoption and use of the messenger. On the dependent side. use of instant messenger seems to have a strong direct impact on task productivity as well as indirect impact through intimacy. Implications are discussed.