BACKGROUND: A growing body of research in aphasia treatment has indicated that greater amount and intensity of treatment is associated with better outcomes in individuals with chronic aphasia. AphasiaScriptsTM is a computerised conversational script training program that simultaneously collects accurate, reliable data about amount and intensity of treatment. AIMS: The purpose of this study was first to investigate the relationship between amount of treatment and improvement on conversational script performance in persons with chronic non-fluent aphasia, and second to investigate the influence of severity of language impairment on this relationship. METHODS and PROCEDURES: We collected computer-generated treatment data from 17 participants with chronic non-fluent aphasia during the 9-week AphasiaScriptsTM treatment protocol. Participants practised three individualised conversational scripts for 3 weeks each. We computed two measures of outcome performance: percent change in script content (script-related words) and percent change in rate (script-related words per minute). OUTCOMES and RESULTS: Amount of treatment varied greatly, from 1.9 to 16.9 hours per week. Amount of treatment was significantly correlated with percent change in script content (r = .67, p<.01) and rate (r = .53, p<.05), after an outlier was removed from the analyses. Severity of aphasia, measured by the Western Aphasia Battery Aphasia Quotient (WAB AQ), was negatively correlated with amount of treatment. When the sample was divided into two severity groups based on WAB AQ scores, amount of treatment was significantly correlated with improvement in content in participants with more severe aphasia, and significantly correlated with improvement in rate in participants with less severe aphasia. CONCLUSIONS: Results are consistent with previous studies that support the relationship between aphasia treatment intensity and outcomes. Severity of aphasia and individual participants' characteristics also impact the relationship between intensity and improvement. Individual participants' treatment trends and characteristics of participants who benefit the most from conversational script training are discussed.