Following recent criticisms of large-scale investigations into the efficacy of aphasia therapy, the use if single-subject research designs has been advocated. This paper considers a range of available designs and describes in detail one study of therapy for an aphasic patient, using a modified multiple-baseline approach. Two targets were chosen for the patient:reducing dyspraxic errors in reading aloud and increasing the use of a sentence-initial grammatical subject in speech. The results of the study appear to show differential improvement on the two targets. These findings are discussed with reference to their implications for further therapy. Whereas the experimental demands of some designs might clash with therapeutic priorities, the modified multiple-baseline approach is sufficiently flexible for clinical use and adequately demonstrates therapeutic effect. Although initially time-consuming, the information provided by regular measurement should make therapy a more efficient process. It is suggested that such studies ought to be incorporated into the clinical routine.