BACKGROUND: Dysarthria is a common post-stroke presentation. Its management falls within the remit of the speech and language therapy profession. Little controlled evaluation of the effects of intervention for dysarthria in stroke has been reported. AIMS: The study aimed to determine the effects of a period of behavioural communication intervention on communication effectiveness and intelligibility, and of the speech disorder's impact on the person with dysarthria. METHODS & PROCEDURES: Eight people with dysarthria following stroke received individually tailored intervention programmes of 16 sessions during an 8-week period. Conversation, and reading aloud of connected speech and of single words were sampled at four points, at intervals of around 2 months: two before intervention and two after intervention. The data were perceptually evaluated by ten listeners, blind to assessment point, for the overall effectiveness of communication (conversation) and for single-word and reading intelligibility. The impact of dysarthria was assessed at the beginning and end of the intervention period. OUTCOMES & RESULTS: The level of reliability of listener ratings was high. There was no evidence of group change between assessment points for measures of communication effectiveness during conversation, or for reading and word intelligibility. Individual participant analysis indicated that five speakers improved in at least one of these three measures. In all cases this followed either stability or deterioration during the 2-month pre-intervention period. There was very little evidence of deterioration during the 2 months after withdrawal of treatment. For three participants no intervention-related speech benefit was demonstrated. Age, dysarthria severity or lesion information did not appear to differentiate those who improved from those who did not. Improvement occurred in all who began the intervention phase between 5 and 8 months following stroke onset. Group data indicated no change in the Dysarthria Impact Profile in respect of three sections (The effect of dysarthria on me as a person; How I feel others react to my speech; and How dysarthria affects my communication with others). There was a significant difference between the start and end of intervention for Accepting my dysarthria, suggesting a reduction in the negative impact of dysarthria. CONCLUSIONS: The results demonstrate that some individuals with dysarthria have a capacity to respond positively to intervention, some months after stroke, and to maintain this improvement following 2 months of no intervention. Consideration is given to how the results of the present study may inform subsequent phases of dysarthria stroke research.