Speech motor changes in six patients with focal unilateral upper motor neuron (UUMN) lesions were characterised using a variety of techniques including listener judgements, speech acoustic analyses, electromyographic and strength measures. Listener judgements of speech understand-ability, intelligibility and dysarthric features indicated mild dysarthria. Diadochokinesis, electromyographic and strength measures corroborated these observations. The findings of this study delineate the characteristics of the dysarthria associated with unilateral upper motor neuron lesions and have important implications for identifying potential upper motor neuron components of other neurogenic disorders of speech and language.