This paper reports on a comparative study of the types and degrees of horizontal and vertical integration occurring within the seed potato industries of the Netherlands and Northern Ireland. Using an integration analysis grid, descriptive models of the internative functions in both industries are presented. Given the superior marketing performance of the Dutch industry, and the way in which this is facilitated by its highly integrated organisational structure, a case is made for the utilisation of both horizontal and vertical integration in improving marketing performance in seed potato industries.