Background : Temporo mandibular is the kind of linked joints with mastication or stomatognation system on orofacial or face which it’s function is both open and close the mouth, chewing the foods, and breath as well. The imbalance of chewing foods between right and left sides caused spasms of one muscle that gets excess pressure. This case caused the functionless of temporomandibular joint that called temporomandibular disorder (TMD. Objective : To determine the incidence of temporomandibular disorder based patient’s gender who visited RSGM UMY in February to March 2018. Research Method: This research was quantitative observational descriptive with Cross Sectional design. . The study was conducted at RSGM UMY during February - March 2018.Examination of the sample used Index Helkimo and data analysis used sampling. Results: the number of respondents 52 most patients had the habit of chewing on one side as much as 33 patients and had the habit of chewing on both sides of 19 patients. Obtained from AiII Helkimo Index category as much as 33 (63,5%) in patient habit of chewing one side, and category Ai0 counted 29 (36,5%) in patient habit of chewing two side. Dysfuntional index (Di0) counted 5 (9,6%) in patient habit of chewing one side and counted 8 (15,4%) in patient habit of chewing two side, Dysfuntional index (Di1) counted 13 (25%) in patient habit of chewing one side and counted 5 (9,6%) in patient habit of chewing two side, Dysfuntional index (Di1I) counted 11 (21,2%) in patient habit of chewing one side and counted 6 (11,5%) in patient habit of chewing two side, Dysfuntional index (DiIII) counted 4 (7,7%) in patient habit og chewing one side and counted 0(0%) in patient habit of chewing two side. Conclusion: the tendency of chew one side with the occurrence of temporo mandibular disorder (TMD).