This study analyses the arguments provided by a convenience sample of 62 Israeli social workers for their preferred ethical principles in terms of ethical theories. Content analysis of arguments given in four different contexts shows that the large majority of social workers in the study based their arguments on either deontological or utilitarian ethical concepts, less frequently using concepts from virtue theory, rights theory and care theory of ethics. However, the analysis reveals a discrepancy: when social workers were requested to justify their rank ordering of ethical principles without reference to a specific practice situation, they most frequently preferred concepts reflecting deontological theory of ethics, such as right intention, universalism, and duty. In contrast, when confronted with a specific practice situation, the social workers' most frequently chosen concepts were relating to results, consequences, and utility, concepts identified with the utilitarian theory of ethics. In view of the findings, the need for more thorough knowledge of a variety of ethical theories and their potential role in ethical decision making in social work practice and education are discussed.