Objective: The aim of this study was to estimate the prevalence of autoantibodies among patients presented to Sultan Qaboos University Hospital (SQUH). Materials: various clinics in SQUH during the period from Jun 2009 to Jun 2011, from patients who were suspected of having autoimmune related disorders. Tests for antinuclear, anti-n-DNA, anti-neutrophil cytoplasmic, anti-islet cell, anti-skin, anti-gastric parietal cell, anti-glomerular basement membrane, anti-reticulin mitochondrial antibodies were performed by the use of indirect immunefluorescence assays on various substrates. ELISA techniques were used to measure anticardiolipin and anti-ENA antibodies. Antibodies to extractable nuclear antigens were also measured by the use of latex agglutination, while anti-thyroid antibodies (ATA & ATMA) were measured by haemagglutination assays. Results: The ages of the patients ranged from >1 year to 85 years. The major number of tests wasrequested by Rheumatology department. In general the majority of patients were female (67%) and among that, Omani nationals constituted 42% of all female patients. A prevalence of autoantibodies of 31% was found and 74% of that was found in Oman patients. Conclusion: The low percentage of positive samplesdoes not necessarily reflect the true ofautoantibodies but is simply due to over requesting of tests.