This paper deals with several architectural issues on a mobile agent-based workflow management system(WFMS). We mainly focus on performance and scalability issues among various architectural issues. We point out three major design issues that are indispensable for designing a mobile agent-based WFMS and find solutions for the issues. We propose an efficient design strategy based on the solutions, i.e. a mobile agent-based ‘2-tier distributed workflow server architecture’, ‘process execution structure through hierarchical delegation’ and ‘ introduction of a non-trivial delegation model’. We also present both a mobile agent based 3-tier run-time architecture and a process execution scenario, which are established according to the proposed strategy. Finally, we show the effectiveness of the proposed method by evaluating performance and scalability through GSPN simulation.