While effective information systems (IS) planning can benefit an organization, IS planning problems still prevail. The aim of this study, therefore, was to characterize IS planning approaches so that ultimately the planning approach used may better match the organization's planning needs. Variations in IS planning approaches were investigated. The a priori expectation was that only a small number of factors would be needed to characterize an organization's needs or its planning approach. A review of previous research on IS planning identified sixteen factors that were important in planning. To identify which of these factors would be good differentiators of IS planning approaches, a three-phase Delphi study was used. Fifty-six of the original 154 experts surveyed participated in all phases of the study. During the survey, respondents added three new factors to be investigated. The final phase requested respondents to rank the factors by their ability to differentiate between IS planning approaches. These rankings clearly established Involvement of Senior Managers in IS Planning, Corporate Context, Impact of IT, Organizational Culture, and IS Planning Motivations as major characterization factors. Since these five factors belong to the objectives and planning process phases, the findings suggest the early planning phases are critical to its success.