Corporate Social Responsibility as a new concept in management science is gaining ground. This work is an attempt in the direction of gaining an insight into this concept, the views held about it and the effect it has on the effectiveness of an organisation. The need to assess the performance of organisations is as perennial as the study of business itself. It is in this regards, that data was collected on two variables of social responsibility and a measure of effectiveness. To achieve its aims, this study is divided into five chapters which are integrative in nature. The first chapter as the introductory chapter entails a discussion of the background of study, statement of problems, limitation and importance of study, the hypothesis as well as the assumptions underlying the study and the relevance of the concept of social responsibility to Nigerian Businesses. The second chapter deals with the review of relevant literatures on the concepts of social responsibility and organisational effectiveness. Chapter three addresses the research methodology used in testing the data collected. The fourth chapter contains the presentation of data as well as the analysis of data while the last chapter contains the conclusion and recommendations. Based on the analysis of the data collected, it was discovered that there may not exist significant relationship between the measures of corporate social responsibility and the level of an organisations effectiveness (except for contribution to government revenue which is discovered to be significantly related to North Brewery's level of effectiveness). Having done this, recommendations are then put forward that social responsibility as a new concept in management science should be a factor business organisations take into account in their operations.