Mediated priming refers to the faster word recognition of a target (e.g., milk) following presentation of a prime (e.g., pasture) that is related indirectly via a connecting "mediator" (e.g., cow). Association strength may be an important factor in whether mediated priming occurs prospectively (with target activation prior to its presentation) or retrospectively. Mediated priming effects were compared for items having a strong (e.g., iceberg--cold--hot) versus weak (e.g., camel--desert--hot) mediator-target association. Priming obtained for both strong and weak mediator-target association conditions in lexical decision tasks (LDTs) conducive to retrospective processing, but only for the stronger items in more automatic LDTs. Results extend recent findings of mediated priming via retrospective processing (e.g., Jones, 2010), and further suggest that a strong mediator-target association is necessary in order for mediated priming to occur prospectively by spreading activation. (Contains 5 tables.)