The current article presents the results of a psycholinguistic study on word stress productivity in Cairene Arabic. Cairene Arabic is a language with a highly predictable placement of word stress based on a very regular foot structure. Participants’ productive stress abilities are evaluated in a reading experiment using Cairene Arabic pseudowords. The main goal is to test what rules, if any, affect the stress assignment in Cairene Arabic, and to what extent metrical structures play a role. The results of this experiment reveal that for Cairene Arabic the internal structure of prosodic words in terms of feet determines the stress assignment for novel words. Frequency patterns of stress are involved as well, but the frequency patterns cannot override the role of stress assignment caused by the regular metrical structure.