Organic software architecture is promising software architecture that provides easiness in its maintenance and support in grow-able environment of software system. In the previous research, this software architecture has been implemented in building web-based healthcare information system. By now, it is still not evaluated yet. Evaluating software architecture is important in the software development phase. In this paper, organic software architecture will be evaluated in order to ensure its quality before it is started to be implemented. ATAM architecture analysis method will be implemented to analyze its risk and trade off of the architecture. The result will show us whether the use of organic framework in developing web-based software is acceptable or not. This research is focusing in using ATAM to evaluate organic software architecture on web-based healthcare information system.