Pruritus among patients with diabetes mellitus is common and may lead to complex dermatological conditions if left untreated. Pruritus can be caused by increased transepidermal water loss (TEWL) and reduced skin hydration.To compare the TEWL and skin hydration in diabetic with non-diabetic patients. To investigate the association between TEWL and skin hydration with HbA1c, fasting blood sugar (FBS), treatment, peripheral neuropathy and age in diabetic patients.This is a prospective, case-control study carried out at a tertiary medical centre in Kuala Lumpur, Malaysia. The TEWL and skin hydration measurements were taken at six different sites in both groups.A total of 146 patients were included (73 cases, 73 controls) with 24 males and 49 females in each group. No significant difference in TEWL and skin hydration between diabetes and non-diabetics. Significant reduction in skin hydration in diabetes patients with FBS>7mmol/L; p=0.005 and peripheral neuropathy; p=0.005. Lower TEWL over the anterior shin in patients with HbA1c>6.5%; p=0.018. Increased TEWL at the flank in patients on insulin injections >1ü/kg/d; p=0.003. A significant reduction in TEWL (p=0.042) and hydration (p=0.036) in those >45 years old in diabetes and non-diabetic groups, respectively.There was no difference in TEWL and skin hydration in diabetes and non-diabetic patients. In the diabetes group, reduction in skin hydration was associated with uncontrolled FBS and peripheral neuropathy but not HbA1c or diabetes treatment. TEWL was lower in patients with FBS>8mmol/L and increase in those with higher insulin requirement.