In SOA environment, software systems are composed of services which are scattered across enterprises and architectures. Security play vital role during the design, development and operation of SOA applications. However, analysis of today's software development approaches reveals that the engineering of security into the system design is often neglected. This may happened due to the fact that the general purpose modelling languages lack the elements for security modelling. As a result, either security is ignored in the model or indicated in a textual way. The post-hoc, low-level integration of security has a negative impact on resulting SOA applications. A Domain Specific Language named "UML-SOA-Sec" is proposed for security modelling along the business process modelling of SOA Applications. © 2012 IEEE.