We used a single-subject research design to examine long-term maintenance of treatment gains in a severely aphasic patient. We used a well-defined therapy protocol [i.e., Computerized Visual Communication System (C-VIC) training] to target production of tense morphology and an assessment specifically designed to measure improvements in the targeted behavior. We first trained Subject #1, a 65-year-old man with a severe nonfluent aphasia, to produce simple subject-verb-object sentences, then tense-marked sentences. Remarkable improvement was shown and was maintained five months after training was terminated. Sixteen months later, he maintained only the ability to produce trained root verb forms. A second training was initiated to examine the parameters of training that affect maintenance. Maintenance was demonstrated up to a year after termination of treatment. We attribute Subject #1's maintained performance to his continued involvement in general C-VIC sentence level therapy following tense training.