This article considers the relevance of the decisions of the International Court of Justice (ICJ) to the development of international law. It contributes to the enduring debate over the place of judicial decisions in the sources of international law in view of the provisions of articles 38(1)(d) and 59 of the Statute of the Court. In addition to describing judicial decisions as ‘subsidiary means’, article 38(1)(d) subjects it to article 59, which provides that decisions are binding only upon the parties to the case. This drafting misadventure has generated more controversy than the drafters could ever have anticipated to the extent that article 59 is equated with the prohibition of the rule of stare decisis, thereby providing justification for the view that judicial decisions are not a source of international law. The core argument of the article is that judicial decisions are a source of international law in practice and even on the wording of article 38(1), albeit subsidiary in hierarchy to the sources listed in article 38(1)(a)–(c). This conclusion is based on a robust analysis of articles 38(1) and 59 as well as the practice they have accumulated over the years.