Background: spondyloarthritis (SpA) is a group of chronic diseases recognized by arthritis and extraarticular lesions e.g. uveitis, enthesitis, dermatological affection. About 35% of SpA patients may present with recurrent attacks of acute anterior uveitis (AAU). Purpose: it was to detect whether patients with idiopathic recurrent AAU who were positive or negative for Human Leukocyte Antigen B27 (HLA–B27) had a frequency of enthesis lesions compared to that seen in patients with SpA. Patients and Methods: a prospective study of enthesis evident on musculoskeletal ultrasound examination was done on sixty patients and twenty controls, the eighty were categorized into 4 groups; group 1 included 20 patients with known SpA group 2 included 20 with recurrent AAU HLA–B27 positive and didn't have SpA aspects group 3 included 20 with recurrent AAU HLA–B27 negative and didn't have SpA and group 4 included 20 healthy controls. Using Madrid Sonography Enthesitis Index (MASEI) twelve enthesis locations were assessed in each participant. Results: a total of 960 entheses sites were examined by ultrasonography in all 80 participants. The MASEI cut-off limit of ≥18 points was 75%, 60%, 45%, and 10% of the participants in the 4 groups; respectively. The MASEI score was significantly higher in groups 1&2 than in groups 3&4. The differences between the two groups were statistically significant. Conclusion: a high percent of HLA–B27 positive patients with idiopathic recurrent AAU without characteristics of SpA have enthesis lesions with about percent to those seen in patients with known SpA.