The paper is an effort to find what determined the success of Polish health reform implemented in 1999 in the Silesian Voivodeship. The problem has been referred to "social capital" proposed by R. Putnam; the first part of the article contains a short description of this approach. Then data concerning health insurance performance in Poland are presented, which confirm that the Silesian Regional Sickness Fund functioned most effectively. As a possible factor influencing present decentralised institutions performance, the situation of the Silesian Region during the mid-war period was described. Autonomy of the region, as well as tradition of social voluntary activity may be a source of "social capital" in Putnam's meaning. Besides, continuity of the Prussian bismarckian health insurance system is presented as a potential source of "institutional memory" also increasing the present reform's chances for success. In the last part of the paper, limitations of applying the "social capital" approach to the Silesian case are presented, such as shortness of the mid-war autonomy period and changes in the cultural structure of Upper Silesia caused by migrations after World War II. Other factors, which could increase the efficacy of the health insurance system, such as relatively high incomes of the region's inhabitants, are also described. Nevertheless, the final conclusion is that social and cultural conditions deriving from historical traditions could have had a significant influence on the process of implementing health reform in 1999.