The main objective of this research was to examine the role of organizational culture congruence in outsourcing performance. Cultural variables of companies that had inter-organizational (outsourcing) partner relationships were analyzed and correlated to their success. The main supposition of this study was the emphasis on the existence of a positive correlation between the congruence of client and vendor organizational culture and outsourcing performance. The epistemological type of research carried out in 2007 was neopositivist and the quantitative and qualitative methodology allowed the triangulation of research, while the method used was multiple case studies. Regarding its aims, the research was exploratory and descriptive, with the objective of mapping the characteristics of the companies studied and establishing relations between the variables analyzed. Sarros et al. (2005)`s questionnaire was used to map organizational culture, while Grover et al. (1996)`s one was used for performance. In relation to means, the research included bibliographic surveys, use of the internet and fieldwork for the collection of primary data with questionnaires and semi-structured interviews. Various statistical analysis techniques were used such as Q-methodology. Organizations were chosen on the basis of convenience, and a total of 12 companies and 476 participants took part in the research. In accordance with the theory, it was found that a search for a partner which can achieve the best result in the outsourcing contract is always desirable. Furthermore, in the interviews it was made explicit that, as in any outsourcing relationship, the interaction between client and vendor goes beyond what is officially covered in the contract, since intangible variables exist that are not specified in the contract. Therefore, if the partners do not have a congruent organizational culture, their relationship can hinder the improvement of partnership quality. The results of the qualitative research sustain the studies carried out. However, the results of the quantitative research cannot be said to confirm the suppositions because results of the statistical analyzes were not significant. Nonetheless, this research demonstrated that even when there was no cultural congruence performance was satisfactory. It was thus shown that the congruence of the organizational culture by itself does not guarantee the success of outsourcing. The research contributed to the organizational literature in a number of ways: by showing the relevance of a methodological application of methods of analysis to a rarely explored theme such as cultural congruence; and by presenting new findings related to the cultural management question that can help to allow the verticalization of the implicit cultural concepts in the definition of managerial policies. Regarding the Administration and Management fields, the research tested in a completely different way a method for the identification and comparison of organizational culture. Even if organizational culture, in isolation of all other variables, does not impact on the performance of inter-organizational partnerships, the possibility of mapping and comparing organizational culture contributes to the increase in the quality of vendors` selection processes. Since it is a novel type of empirical research the non-confirmation of the suppositions creates the opportunity for new studies that seek to analyze multiple partner relations of the same client in order to investigate the existence of congruence in organizational culture and the level of its impact on the performance of various contracts.