A survey instrument was developed to elicit information useful in characterizing the membership of hog marketing cooperatives and to identify benefits and costs expected and perceived by members. An empirical application investigates the role of marketing cooperatives in the Illinois pork industry. Producers in general agreed there were benefits of membership in a hog marketing cooperative although perceptions of the nature and extent of these benefits varied. Important differences were identified between perceptions of producers with small operations and those held by other producers.