Background: Temporomandibular disorder (TMD) is caused by the movement disharmony of temporomandibular joint. Patients aged 24-45 years old show symptoms of TMD the most compared to other age ranges. Objective: to observe TMD in Patients Aged 24-45 Years Old of Dental and Mouth Hospital of Muhammadiyah University of Yogyakarta on February to March 2018. Method: Cross sectional design was used in this observational descriptive research. The respondents were patients of Dental and Mouth Hospital of Muhammadiyah University of Yogyakarta on February to March 2018 who were selected through certain criteria. Helkimo index was used to find out the number of TMD case. The data were analyzed by using Frequency distribution. Results: 52 patients of Dental and Mouth Hospital of Muhammadiyah University of Yogyakarta on February to March 2018 were classified into early adult (aged 24-35) consisting of 33 respondents (63,5%) and late adult (aged 36-45) consisting of 19 respondents (36,5%). Based on Anamnestic index, 11 respondents of early adult (21,2%) and 13 respondents of late adult (25,0%) are categorized as AiII. Based on Disgnostic Index, the result shows that 18 samples (34,6%) are categorized as DiI, 17 samples (32,7%) are DiII, and 4 samples are DiIII. Conclusion: The Description of Temporomandibular Disorder in Patients Aged 24-45 Years Old of Dental and Mouth Hospital of Muhammadiyah University of Yogyakarta on February to March 2018 are based on Anamestic Index and Dysfunction Index. Anamestic index based description shows that 65,4% patients suffer TMD with further indication that early adults have tendency to show severe symptoms. Meanwhile, the Dysfunction index shows that 75% patients suffer TMD that early adults are more prone to this.