One of the most fragile stratums of every society is the people with certain disabilities, especially educable mentally retarded children. Some of the most tangible difficulties of these people are seen in their perceptual and motional abilities (coordination, balance, atmospheric awareness, time awareness, physical awareness and sense of direction). Overcoming these inabilities requires the integration of environmental information and decision making for performance of a special function. The objective of the present research is to investigate the effects of eight weeks of Tai-Chi exercises on status parameters of Kyphosis and balance among educable mentally retarded children. The research sample is consisted of 30 educable mentally retarded children suffering from Kyphosis abnormality. The sample individuals were selected from welfare centers of Tehran. After selection of samples, prior and post to execution of the protocol, the individuals were measured in terms of Kyphosis angle, chest expansion, coefficient of Delmas, spine extension and static and dynamic balances respectively through flexible rulers, tape measure, stoke test and Y test. The educable mentally retarded children were assigned to two 15 individual groups of experimental (age average of 11.6 years; average height of 142.30; average weight of 39.26kg) and control (age average of 11.06; height average of 139.83 and weight average of 35.86kg). The subjects of the experimental group were participated in an 8 week course of Tai-Chi exercises in three weekly 45 minute sessions. These exercises included a 10 minute warm-up, 30 minutes of Tai-Chi movements and 5 minutes of cool-down. During this time, the subjects of the control group were not incorporated into any exercise. By the use of the Shapiro-Wilk test, the normality of data distribution was investigated and approved. Also the Leon test was used for investigation of equality of the variances. Afterwards, descriptive statistics including average and standard deviation and inferential statistics including co-variance analysis were performed on the results. Tai-Chi exercises had been effective on improvement of Kyphosis angel, Delmas coefficient, chest expansion, spine extension and static and dynamic balances among the subjects of the experimental group. Tai-Chi exercises can have a significant effect on improvement of Kyphosis and other mentioned variables among educable mentally retarded children. These exercises can also be used with the aim of improving and increasing the presence of mentally retarded children in sports events and the society as well as encouragement of these children towards more activity.