The author divides Cuba's socialist juridicial development into three major periods: 1959 to 1963, the founding stage of social change underscored by a series of laws aimed at political and economic goals; 1964 to 1969, characterized by important initiatives such as the Popular Courts and collective legal offices organized to provide legal counseling to needy groups; and 1970 to the present, a period of major reorganization of the institutionalization of the judicial and political system. Cuba's progress is placed in the context of socialist theory regarding legal system development. The paper examines relevant statutes enacted during the 1960's and 1970's in terms of either being the cause or the effect of social change. It emphasizes that legal developments in the first decade of revolutionary rule were instruments for social change and that legal development was not seen as an end in itself. As revolutionary leaders came to recognize a widespread practice of poor compliance with the law, they moved to institutionalize the legal system. This shift is illustrated by analyses of the 1976 Socialist Constitution, the 1973 and 1977 reorganizations of the judicial system, and the 1976 reorganization of the state's central administration. A review of the antecedents and characteristics of the 1979 Penal Code concludes that it continues earlier practices accepted in Cuban jurisprudence while moving in the direction of a new definition of crime and sanctions shared by other socialist systems. The article includes 49 footnotes.