This paper examines the following basic issues of leadership in research units: (1) characteristics of the leader and the functions performed by him that predict the image of his quality; and (2) the role of leadership in enhancing the performance of the research unit. Analysis is based on data collected on 1460 research units in six countries for the second round of International Comparative Study on Organization and Performance of Research Units. Variations in the characteristics and role of leadership in different institutional settings and countries are analyzed through POSCOR (ranking programme based on partially ordered sets). Stepwise multiple regression analysis was used to examine the common pattern of relationship of various indices of leadership with the image of leader's quality and three measures of effectiveness — scientific, user-oriented and administrative. Analysis was repeated for each country to explore the stability in the pattern of relationships and to identify universal indices that have consistent relationships across countries. Implications of the results are discussed.