Although a number of studies have examined organisational culture and effectiveness, such studies have often resulted in inconclusive findings. Through an intensive ethnographic case study, this study explores and analyses this relationship in the context of a knowledge-intensive firm. The study adopts the three perspective framework of organisational culture (see Martin 1992, 2002) as the theoretical framework through which the links between organisational culture and effectiveness are examined. The adoption of the three perspective framework throws rich insights into the nature of organisational life. However, although the study finds overall support for the three perspective framework, it suggests that this framework could be strengthened in regard to the conceptualisation of integration and fragmentation, particularly in the context of an organisation based in a developing country undertaking work for the MNCs. Similarly, the adoption of the different theoretical approaches to effectiveness leads to the identification of a series of interesting measures of effectiveness. In this regard, an integration based analysis highlights the certainty of the measures of effectiveness whereas the differentiation and fragmentation analyses show the problematic, inconsistent and transient nature of effectiveness. The adoption of the three perspective framework sheds interesting insights into culture effectiveness relationship. While the integration perspective presents a positive relationship, the differentiation perspective holds that the inherent inconsistencies and conflicts have a negative influence on effectiveness. The fragmentation based analysis shows that culture is a neutral factor vis-a-vis effectiveness. Furthermore, the ironies, contradictions and ambiguities are shown to have a negative influence in this regard. This work therefore concludes that the argument that there is a relationship between culture and effectiveness is the result of adopting a particular analytical lens (generally, integration perspective). This study also shows that the proposition that non-financial aspects of effectiveness mediate the relationship between organisational culture and financial performance can work only in the case of adopting an integration perspective