Purpose: The importance of oral motor abilities in stuttering occurrences has been continuously debated and discussed. The purpose of this study was to determine whether there would be a difference in speech mechanism and motor abilities between adults who stutter (AWS) and adults who do not stutter (AWNS). Methods: A total of 34 subjects participated in this study: 17 AWS (14 males and 3 females; mean age, 32 yrs 9 months) over 20 years old and 17 AWNS matched chronological age and sex with the former group. Each of the participants was directly examined on the basis of 13 items of structure and 17 items of function of speech mechanism. Results: There was no significant difference in speech structure and function between the two groups. Conclusion: In speech mechanism and motor ability assessment, a significant difference was not found in any areas, including structure and function, between AWS and AWNS. However, there may be individual variations, and for this reason, if there are any areas that might be problematic, even in the most fundamental areas, this should be taken into careful consideration. More considerable examination should be taken than direct observation of oral structure and function when it is doubtful.