The majority of requests for a preliminary ruling from the EU Court of Justice comes from lower national courts. This is surprising because such courts are, contrary to the highest national courts, not obliged to refer on the basis of Article 267 TFEU. This article examines why Dutch and Irish lower courts have decided to refer or not in the absence of such a legal obligation. It does so on the basis of an analysis of court decisions complemented with 45 interviews with judges and legal secretaries. [---]