Introduction Femoroacetabular Impingement Syndrome (FAI) is a multifactorial hip disorder that originates from abnormal contact between the femoral head-neck and the acetabulum, ultimately leading to joint damage. The most precise definition of FAI, established in 2016, describes the condition as a motion-related hip disorder characterised by pain symptoms, restricted mobility and characteristic imaging findings. FAI manifests in three main morphological types: Cam, where bone growth on the femur causes abnormal head-neck offset, Pincer, where the acetabulum excessively covers the femoral head and Mixed which contains features of both previous mentioned types. The alpha angle is a key radiographic measure used to diagnose Cam-morphology FAI. However, studies have demonstrated that there is considerable variability in the reliability of its measurement, with intraobserver reliability typically higher than interobserver consistency. Aim The aim of the study was to determine variability of alpha angle measurements on radiographs, with use of the inter- and interobserver reliability in assessing the alpha angle of the hip joint. Material and methods A retrospective observational study was conducted on 72 radiographs of adult patients diagnosed with FAI who had undergone arthroscopic osteoplasty of the hip joint. The patients' axial radiographs were evaluated by three independent investigators. Measurements were taken preoperatively and postoperatively in two probes before and after the blinding process was initiated. Results Value of Inter–Observer Reliability of alpha angle measurements in preoperative group (0,44- 0,62) as well as in postoperative group (0.48- 0,50) is moderate. Value of intra class reliability come with significant variability, as is lower in postoperative group (0,46- 0,89) and higher in postoperative group (0,79-0,96). Conclusions Constituency of measurements of alpha angle might by influenced by lack of observer’s experience.