Type 1 diabetes mellitus (T1DM) remains the most common form of diabetes in childhood. The incidence of type 1 diabetes is continuously increased. Zinc transporter protein 8 antibodies (ZnT8A) measurement can be helpful in detection of suspected new cases of type 1diabetes when other islet auto antibodies are negative. We evaluated the role of ZnT8A in diagnosis of new cases of T1DM in comparison to islet cell antibody (ICA), and assessed its prediction value among siblings. 31 of newly diagnosed T1DM patients and 55 age and sex matched healthy siblings were included. Measurements of ZnT8A and ICA was carried out by ELISA. ZnT8A had 45% sensitivity and 69% specificity while ICA had 64.5% sensitivity and 83.64% specificity. 22.6% of diabetic patients had high level of ZnT8A as compared to 20% of siblings (P< 0.001 and P < 0.001, respectively). 28.6% of diabetic patients with high titer ZnT8A had positive ICA (P <0.04) as compared to 63.6% in sibling group (P<0.001). It is concluded that ZnT8A and ICA play an important role in diagnosis and prediction of T1DM cases.