Our study aimed to investigate: the prevalence of autoantibodies related to organ-specific disease; the prevalence of some autoimmune diseases (AID) in Egyptian Turner syndrome (TS) patients; and the association of autoimmunity with patients' karyotypes. Eighty TS patients were subjected to history, auxological assessment and measurement of antithyroid peroxidase antibody (ATPOAb), antithyroglobulin antibody (ATGAb), anti-tissue transglutaminase IgA antibodies (ATTIgAAb), anti-glutamic acid decarboxylase-65 antibodies (GAD-65-Ab) and anti-adrenal cortex antibodies (AACAb). Of the 80 TS patients, 54 (67.5%) were seropositive for one or more autoantibodies. Thirty-five percent were positive for ATPOAb, 15% for ATGAb, 12.5% for ATTIgAAb, 3.75% for Anti-GAD-65Ab and 1.25% for AACAb. There was a non-significant association between the 45,X karyotype and overall prevalence of autoantibodies (p=0.20), while IsoXq was associated with increased prevalence of ATPOAb (p<0.01), ATGAb (p=0.01) and anti-GAD-65Ab (p=0.02). Thus, female TS patients face a high prevalence of autoimmunity and associated AID.