On-line monitoring during study can be influenced by the relatedness shared between the cue and target of a paired associate. We examined the effects on people's judgements of learning (JOLs) of a different kind of relatedness, which occurs in a list organised into sets of categorically related words and unrelated words. In two experiments, participants studied a list of words organised into a series of sets of four categorically related words or four unrelated words. In Experiment 1, JOLs were made immediately after each word had been studied, and JOL magnitude was greater for related than unrelated words. In Experiment 2, JOLs were delayed after study and, as expected, they were substantially greater for related sets of words. Serial position effects (an increase in JOL magnitude across the words of a related set) were evident with immediate JOLs but not with delayed JOLs. The relatedness effect was not present early in the list for immediate JOLs but was present throughout the list for delayed JOLs. We conclude by discussing some preliminary explanations for these new phenomena.