Some applications, like medical or satellite imagery systems for example, require a real time implementation of the JPEG2000 coder. This paper describes a possible implementation on a platform based on the MPC74XX processor, and a complexity study for this platform is presented. After a brief summary of the different components of a JPEG2000 coder, a description of the MPC74XX processor and an example will be given to illustrate its possibilities. Then some measurements and evaluations of the complexity of JPEG2000 will be described. of JPEG2000 complexity is presented in this paper. The work presented here has been conducted in the framework of the PRIAM IST European project (Platform for Real-time Interactive Access to Mega-images). This project will demonstrate the properties of the JPEG2000 standard for very large images in the medical and satellite domains.