The purpose of this essay is to exhibit certain crucial shortcomings of some representative empiricist and anti-empiricist ethical theories and to sketch an empiricist ethics which is not exposed to these objections and adequate to our cognitive and practical position in the world. The discussion falls into two parts. Part I, which is mainly critical, begins with a general distinction between empiricist and anti-empiricist ethical theories and surveys the assumptions which are permissible to the former in the sphere of factual beliefs, practical attitudes and logical inference (section 1). It then examines the central theses of three kinds of empiricist ethical theory, namely utilitarian, contractual and emotivist theories (section 2) and of three corresponding kinds of anti-empiricist theory which can be viewed as attempts at correcting the faults of their empiricist counterparts (section 3). Part II, which is mainly constructive, contains a sketch of a new empiricist ethics (section 4) and in its light a brief discussion of various types of moral system (section 5) of the limits of moral pluralism and the nature of moral argument (section 6).