In the previous studies, some characteristics of flaccid dysarthria patients have been studied mainly in two aspects: their difficulties in articulation and their metrical dysfunction. Therapeutic research on the articulation impediment of the patients have been carried out extensively (Yorkston, 1981). However, their phonetic characteristics have been less well-studied. The aim of this paper is to measure and describe some phonetic differences between the normal speaker group (six speakers) and the flaccid dysarthria patient group (six speakers in three different degreed of severity). Two types of short sentences comprising of subject-object-verb, i.e. declarative and yes-no question sentences, were recorded to investigate some phonetic characteristics of these two groups of speakers. The two groups (normal group vs. patient group) show differences in yes-no question boundary tone (H% vs. HL%), pitch range (wide vs. narrow), duration (short vs. long) and intensity (strong vs. weak) of sentence final verb endings in Korean.