This study examines the nature of relationships between marketing information systems (MktIS) effectiveness and market orientation (MO) dimensions. The study utilises a canonical correlation approach in order to determine the relationship between the two constructs. The results indicate that MO and MrkIS effectiveness are related concepts. More interesting is the relationship of customer and competitor orientation, especially with the external dimensions of the MrkIS effectiveness. These are the first empirical data that demonstrate a strong relationship between the customer and competitor orientation dimensions of the MO concept with the marketing procedural improvement and the two external dimensions of MrkIS effectiveness, namely customer knowledge and market responsiveness. On the other hand, interfunctional coordination is more closely related to internal climate of company's MrkIS effectiveness. Based on the results, managerial implications are discussed. Limitations of the study as well as future research directions are also addressed.Journal of Targeting, Measurement and Analysis