Judge Alejandro Álvarez had already developed a theory of a ‘new international law’ when he joined the first bench of the International Court of Justice in 1946. During his time at the Court, he elucidated his theory by means of Individual or Dissenting Opinions, always stressing the importance of the Court for judicial lawmaking. The aim of this article is to present Álvarez's concept of a ‘new international law’ and to analyse some of his individual and dissenting opinions with respect to his theory, with additional emphasis on the lawmaking function of the Court as an integral part of his approach.