Background: Constraint-induced aphasia therapy (CIAT) offers potential benefits to individuals with history of aphasia-producing ischemic stroke. The goals of this pilot study were to implement the original German CIAT protocol, refine the treatment program, and confirm its efficacy in patients with chronic aphasia. Material/Methods: We translated and modified the original CIAT protocol to include a hierarchy of individual skill levels for semantic, syntactic, and phonological language production, while constraining non-use behaviors. Three male participants with moderate to severe post-stroke aphasia received CIAT 3-4 hours/day for 5 consecutive days. Pre and post-testing included formal language evaluation, linguistic analysis of story retell, and mini-Communication Activity Log (mini-CAL). Results: Substantial improvements in comprehension and verbal skills were noted in 2 patients with an increase in the total number of words (31% and 95%) and in number of utterances for story-retell task (57% and 75%). All participants demonstrated an improvement on at least one linguistic measure. No subjective improvements on mini-CAL were noted by any of the participants. Conclusions: Given that the duration of treatment was only 1 week, these linguistic improvements in post stroke aphasia participants were remarkable. The results indicate that the CIAT protocol used in this study may be a useful tool in language restoration after stroke. These initial findings should be confirmed in a larger, randomized study. © Med Sci Monit, 2008.