The effects of two therapy methods in the treatment of picture naming problems are compared, using a within-patient design with 12 adult patients with chronic acquired aphasia. We contrast techniques that require the patient to process the meaning corresponding to the picture name (semantic treatment) with those that provide the patients with information about the phonological form of the name (phonological treatment). With each method, patients either had 4 sessions of treatment over one week, or 8 sessions over two weeks. Both methods cafsed day-by-day improvement that was specific to the actual items treated. Both methods resulted in significant improvement in naming when this was measured one week after the end of treatment, with a small, but significant advantage for the semantic treatment; this is mainly due to improvement that generalizes to untreated items. We conclude that specific and theoretically motivated treatment methods can cafse significant improvement in the word retrieval ability of patients with chronic aphasia.