In two experiments, the performance of patients with frontal lobe lesions was examined on implicit and explicit tests of conceptual memory for organized lists of words. Frontal patients exhibited normal levels of conceptual priming on implicit category production and free association tests, but they exhibited impaired memory performance on explicit category- and associate-cued recall tests. The findings of normal performance on implicit conceptual tests suggest that frontal patients do not have a basic deficit in semantic processing of individual items. Impaired performance on explicit cued recall tests may be related to deficits in the use of organizational encoding and strategic retrieval processes.