Background: This research is a field study dealing with practical aspects of speech with children who were diagnosed as having attention deficit hyperactivity disorder (ADHD). In the study speech patterns of children with ADHD were compared when they were under the influence of short-acting Methylphenidate to the time they were without short-acting Methylphenidate. Methods: Neutral observers observed 26 children in the 3nd to 5th grade, mean age 10.34 years old, who were diagnosed as having ADHD. None of the participants had a history of speechlanguage deficits. The study was conducted in a randomized cross over design procedure. A 0.3 to 0.5 mg/kg of short-acting Methylphenidate was administered to all the participants. Their speech patterns were observed while they were under the influence of short-acting Methylphenidate and compared to the time when they were not under the influence of the medication. Results: The results of the questionnaire, Conners' Teacher Rating Scale Revised-Long, showed the participants were assessed as having above the norm symptoms of ADHD by the questionnaire completed by their teacher. The observations showed less problematic speech behavior in the following three speech patterns pursuant to using short-acting Methylphenidate: voice intensity, rate of speaking, and interruption of someone else's speech. Pauses during the speech increased while the participants were under the influence of shortacting Methylphenidate. Improvement in the combination of three speech variables may make the difference between loud, fast, blurred, unclear, interrupting speech patterns that children with ADHD sometimes have without short-acting Methylphenidate as compared with the time when they behave appropriately in the classroom while they were administered a short-acting Methylphenidate. Conclusion: The information that short-acting Methylphenidate had a positive influence on speech patterns of children with ADHD should be taken into account when considering prescribing short-acting Methylphenidate to children who were diagnosed as having ADHD.