With the increasing use of computers in business information security has also become a key issue in organizations. Risk assessment in organizations is vital in order to identify threats and take appropriate measures. There are various risk assessment methodologies exist which organizations use for risk assessment depending the type and need of organizations. In this research OCTAVE methodology has been used following a comparative study of various methodologies due to its flexibility and simplicity. The methodology was implemented in a financial institution and results of its efficacy have been discussed.