During the past years, the agricultural sector in Bulgaria entered an important stage. The country is a member of the EU. This fact speeding up the adoption and application of the different CAP regulations. In its way of accession to the EU, the country becomes faced with the challenge to increase the effectiveness and competitive power of agricultural production. Most part of the existing agricultural farms are small-sized. They lack sufficient market information, good management and access to markets and credits. The main problems is how the agricultural producers can better themselves in the conditions of insufficient financial resources and limited access to the market. One possibility to reach this goal is to substitute the limited production factors for ones that are more accessible. Such relatively easily accessible factor is the people to join together in pursuing their common objectives. This can be achieved through establishment of organizations of agricultural producers, which however requires a certain level of social capital. Using case studies from Bulgarian agricultural organizations the author highlights key factors affecting producer organizations' success.