This paper presents the result of an empirical study which examines the relationship between organizational information requirements and IS planning typology, and which measures the effectiveness of IS planning by the fitness of information requirements and IS planning typology. From previous research on IS planning, several variables for each construct are identified for generating four hypotheses. This study uses data that was collected and organized in a two-phase process: 1) a pilot study on fifteen Korean firms including manufacturing, banking, and service industries; 2) a questionnaire survey of 1000 large firms in Korea, of which 187 firms responded. thirteen questionnaires were omitted from the analysis because of missing or inappropriate responses, leaving a final sample of 174 valid questionnaires. The results indicated that organizational information requirements were positively correlated with IS planning typology. Testing the relationship between the level of IS planning and IS planning effectiveness revealed that the higher the level of IS planning was, the higher IS planning effectiveness was.