The mean β‐glucuronidase concentration in the adrenal homogenate of male patients with cancer was found to be significantly lower than that of male patients without cancer. The patient's age appeared to be without effect on the adrenal β‐glucuronidase concentration; an influence of the nutritional status independently of the disease could not be evaluated. Several cancer patients were treated with corticoids; this treatment was without effect on the adrenal β‐glucuronidase concentration. Histochemically, the highest β‐glucuronidase activity was localized in the zona glomerulosa in over 50% of cases; the other cortical layers or the medulla showed the highest activity in the remaining cases. The distribution of cell groups with β‐glucuronidase activity was patchy. The localization of β‐glucuronidase activity in the adrenals of patients with or without cancer was similar, but the number and intensity of areas with β‐glucuronidase activity was decreased in the adrenals from cancer patients. Although the actual function of β‐glucuronidase in the adrenal is not known, the preeminent localization in the glomerulosa and the lack of influence by stress and by steroid treatment on its concentration suggest a specific function in aldosterone metabolism. The changes in the adrenal β‐glucuronidase concentration in cancer patients may be an indication of disturbance in aldosterone metabolism.