Auditory-verbal short-term memory deficits (STM) are prevalent in aphasia and can contribute to sentence comprehension deficits. This study investigated the effectiveness of a novel STM treatment in improving STM (measured with span tasks) and sentence comprehension (measured with the Token Test and the Test for the Reception of Grammar, TROG) in a person with severe aphasia (transcortical motor). In particular, the research questions were: (1) Would STM training improve STM? (2) Would improvements from the STM training generalise to improvements in comprehension of sentences? STM was trained using listening span tasks of serial word recognition. No other language or sentence comprehension skills were trained. Following treatment, STM abilities improved (listening span, forward digit span). There was also evidence of generalisation to untreated sentence comprehension (only on the TROG). Backward digit span, phonological processing and single word comprehension did not improve. Improvements in sentence comprehension may have resulted from resilience to rapid decay of linguistic representations within sentences (words and phrases). This in turn facilitated comprehension.