The concept of the Plan Development Process is based on the possibility of application of the Unifi ed Process methodology on urban planning process. Viewed as a way of organization of planning tasks, the urban planning process may be analyzed in the area of complex process management, particularly the area of software development management which gave rise to some of the most advanced methodologies for arrangement of tasks and standards pertaining to formal methodologies for defi nition and implementation of program solutions. Complex process management and urban planning face problems of similar complexity. The Unifi ed Process methodology is one of the most successful methods for the organization of software development process. Through the application of the Unifi ed Process methodology on urban planning process, the concept of plan development was formulated, as a methodology for contemporary planning process and the corresponding metamodel as the fi nal level of abstraction bringing together all knowledge of a given domain.