Abstract
In this article we have analyzed both the main traits of efficient firms and the main sources of firms' efficiency through a representative sample of 2.029 small and medium size Catalan firms. Our results demonstrate the importance for managers of realizing that firms' efficiency shows a significant improvement when advanced ICT uses are combined with human resources practices focused on the promotion of workers autonomy, flexibility and decentralization of firm's decision making process, and with the adoption of employees assessment systems based on human values.