This paper presents an integrated environment, called MetaPlex; for organization and information systems development. The kernel of MetaPlex is a knowledge base management system which captures the semantic primitives of a domain at the meta level and uses these primitives to describe target systems. Three levels of abstraction are used in MetaPlex for representing knowledge: the axiomatic, median, and instance levels. The MetaPlex Language Definition System is used to name the object types in the domain of interest and to define the attributes, relations, and descriptions which can be used by these object types. The structural knowledge of the domain in general is thus captured at the median level. Knowledge of the domain captured at the median level is used by the MetaPlex Specification System to define a target system at the instance level. A rule-based inference engine is embedded in the MetaPlex environment as an intelligent assistant to help end users. The expertise of a designer can be codified into a rule set which can assist users in classifying an object, in decomposing a high level system component, or in clustering the detailed components at the lower level. Both topdown and bottom-up approaches for systems development are thus supported. A layered approach has been proposed to manage the dynamics of such a metasystem environment. An enterprise model has been developed to demonstrate the usage of MetaPlex and the integration of organization and information systems modeling. Directions for future research are also discussed.