Priming effects on picture naming and categorizing were investigated. The target pictures were line drawings of common objects. After a prime (either a picture or a word), a target picture appeared and subjects (32 undergraduates) responded its name (naming task) or its category name (categorizing task) as quickly as possible. Four types of prime-target relation were: identical pairs (ID), related pairs (RE; both items belong to the same semantic category), unrelated pairs (UN), and no prime condition (NP). For naming task, facilitation was obtained in ID condition but not in RE condition. For categorizing task, approximately the same amount of facilitation was observed in both ID and RE conditions. The results indicate that picture priming effects are dependent upon the identification levels of target pictures and are discussed in terms of category identification models of picture processing.