Adrenoleukodystrophy (ALD) and its adult variant adrenomyeloneuropathy (AMN) are X-linked diseases associated with a deficiency in the peroxisomal degradation of saturated very long chain fatty acids (VLCFA) resulting in an accumulation of VLCFA in the central and peripheral myelin, the adrenal cortex and the testis. Adrenal insufficiency with clinical hypocortisolism occurs in approximately two thirds of the patients with AMN. We studied the circulating adrenal hormones17α -hydroxyprogesterone (17α -OHP), androstenedione and dehydroepiandrosterone sulphate (DHEAS) in 63 male AMN patients (age 17- 65 years) and the DHEAS serum levels in 95 healthy male controls (age 30- 65 years). 34 of the patients presented with the phenotype of only spinal cord and peripheral nerve disability without hypocortisolism, 29 of the patients presented with the phenotype of either additional hypocortisolism or Addison’s syndrome only. Normal 17α - OHP concentrations were found in all patients with no significant difference between patients without and with hypocortisolism (6.07 ± 0.61 nmol/l and 4.76 ± 0.37 nmol/l). Androstenedione concentration was significantly (p < 0.01) lower in patients with hypocortisolism (2.99 ± 0.65 pmol/l versus 5.71 ± 0.68 pmol/l). As serum levels of DHEAS are age-dependent we divided the two groups into two subgroups each (subgroup one: age 17- 40 years, subgroup two: age 41- 65 years). The DHEAS concentration of patients without and with hypocortisolism was significantly (p < 0.01) lower in both subgroups (1: 4.35 ± 0.84 μ mol/l, n = 15, 2. 15 ± 0.28 μ mol/l, n = 19; 1: 1.90 ± 0.57 μ mol/, n = 21, 2: 0.96 ± 0.29 μ mol/l, n = 8) compared to controls (1: 9.0 ± 0.96 μ mol/l; 2: 5.21 ± 0.25 μ mol/l). In conclusion, androstenedione and DHEAS serum concentrations are subnormal in all AMN patients and may therefore serve as sensitive markers of the adrenal function in adrenomyeloneuropathy. Adrenoleukodystrophy (ALD) and its adult variant adrenomyeloneuropathy (AMN) are X-linked diseases associated with a deficiency in the peroxisomal degradation of saturated very long chain fatty acids (VLCFA) resulting in an accumulation of VLCFA in the central and peripheral myelin, the adrenal cortex and the testis. Adrenal insufficiency with clinical hypocortisolism occurred in about two thirds of the patients with AMN. We studied the circulating adrenal hormones 17α-hydroxyprogesterone (17α-OHP), androstenedione and dehydroepiandrosterone sulphate (DHEAS) in 63 male AMN patients - 65 years) and the DHEAS serum levels in 95 healthy male controls (age 30-65 years). 34 of the patients presented with the phenotype of only spinal cord and peripheral nerve disability without hypocortisolism, 29 of the patients presented with the phenotype of either additional hypocortisolism or Addison’s syndrome only. Normal 17α - OHP concentrations were found in all patients with no si gnificant difference between patients without and with hypocortisolism (6.07 ± 0.61 nmol / l and 4.76 ± 0.37 nmol / l). Androstenedione concentration was significantly (p <0.01) lower in patients with hypocortisolism (2.99 ± 0.65 pmol / l versus 5.71 ± 0.68 pmol / l). The serum levels of DHEAS are age-dependent we divided the two groups into two subgroups each (subgroup one: age 17-40 years, subgroup two: age 41-65 years). The DHEAS concentration of patients without and with hypocortisolism was significantly (p <0.01) lower in both subgroups (1: 4.35 ± 0.84 μ mol / l, n = 15,2.15 ± 0.28 μ mol / l, n = 19; 1: 1.90 ± 0.57 μ mol / n = 21, 2: 0.96 ± 0.29 μ mol / l, n = 8) compared to controls (1: 9.0 ± 0.96 μ mol / 1; 2: 5.21 ± 0.25 μ mol / concentrations are subnormal in all AMN patients and may therefore serve serve as sensitive markers of the adrenal function in adrenomyeloneuropathy.