Sveriges medeltida personnamn (SMP) is the name of a dictionary of personal names from medieval sources from Sweden, based on large collections in Uppsala. The forename-part of the dictionary is in course of publication. The aim of this paper is to review how the division between the categories forenames and bynames/surnames is treated in the dictionary. The authorfinds that the division to a large part is not problematic, but that some cases present lexical or theoretical challenges, that has not always been treated in a consistent manner. The problematic cases can furthermore be of considerable onomastic interest.