The presented paper is relevant, as it presents the results of fatigue tests of titanium alloy. The purpose of the article is to describe the use of the hypothesis of linear damage summation when processing the results of fatigue tests. In the study, the authors used empirical methods such as indirect observation of the object under study, description, and measurement of technical influences exerted on it by an artificial means. The linear regression analysis to establish the relationship between stress and durability was also used. The endurance limit of the titanium alloy was determined, which lies in the range from 460 to 480 MPa with the number of cycles from 105 to 108. It was concluded that the use of the linear damage summation hypothesis in processing the results of fatigue tests entails a satisfactory practical accuracy of the calculation of endurance limit