This chapter argues there is a “pull” toward cross-fertilization on procedural questions, meaning cross-fertilization between international courts and tribunals may be more likely for procedural issues than in substantive law. It describes cross-fertilization in relation to procedural issues. Procedural cross-fertilization is a process and is not just about borrowing by adjudicators, but involves contributions by a range of actors. Three considerations facilitate procedural cross-fertilization and even make it somewhat likely: the discretion of adjudicators on procedural issues, adjudicators’ duty to decide numerous procedural issues, and sociological considerations concerning the circulation of a small number of personnel across multiple fora. However, two considerations counterbalance adjudicators’ broad discretion. On one hand, control mechanisms operated by states push adjudicators to remain faithful to their mandates, limiting the space for procedural cross-fertilization. On the other hand, procedural cross-fertilization feeds and is fed by an emerging model of international due process that is affecting all areas of international adjudication.