Results showed that the mean C-peptide levels were 0.78 ± 1.26 nmol/l and 1.49 ± 1.49 nmol/l in the T1D and controls, respectively. Half (50%) of the T1D patients had C-peptide ≥0.2 nmol/l.***Recently diagnosed T1D patients may have high levels of residual endogenous insulin secretion. Here, INS is linked to type 1 diabetes mellitus.