Objectives: Anti-C1q antibodies have been described in many immune-complex diseases like SLE. The aim of this study was to detect anti-C1q antibody in patients with chronic HCV infection with autoimmune extra hepatic manifestations in comparison to those without, SLE and to normal healthy individuals. And to analyze the association of anti-C1q antibodies with clinical features of HCV-related extra-hepatic manifestations.Patients and methods: Anti-C1q antibodies were assessed by ELISA in 51 patients suffering from HCV with autoimmune extrahepatic manifestations, 40 HCV patients without those manifestations, 25 SLE patients, in addition to 40 healthy subjects.Results: Positive anti-C1q antibodies were found in 16 HCV patients with extra-hepatic manifestations (16/51; 31.37%), 6 HCV patients without those manifestations (6/40; 15%), 15 SLE patients (15/25; 60%), and 3 healthy control subjects (3/40; 7.5%). The prevalence of lymphoma and cryoglobulins in patients with HCV and positive anti-C1q antibodies was significantly higher than in those with negative anti-C1q antibodies. Anti-C1q antibodies negatively correlated with C4 in HCV patients. While positive correlation between viral Load and the level of anti-C1q antibodies was found.Conclusion: Prevalence of anti-C1q antibodies in HCV infected patients with autoimmune rheumatic manifestations was increased in our study. Anti-C1q antibodies were associated with low C4 levels.