The paper describes the role of endogenous glucocorticoids in the pathogenesis of open-angle glaucoma. As to steroid-induced glaucoma (SG), however, indicators of systemic and local cortisol metabolism are yet underinvestigated. Aim — to determine and compare systemic (plasma) and local (aqueous humour) cortisol concentrations in patients with SG and other types of glaucoma (OTG). Material and methods. A prospective analysis was conducted in 64 patients who underwent plasma and aqueous humor sampling. All the patients were divided into 4 groups: group 1 — 11 patients with steroid induced ocular hypertension (SOH) and SG; group 2 — 31 patients with OTG; group 3 — 10 patients on steroid therapy (ST) without a so called ‘steroid response’; group 4 — the controls (12 patients with cataract). Results. The mean cortisol levels in plasma and aqueous humour were the following: 177.5±29.4 ng/ml and 53.1±12.2 ng/ml in patients with SOH and SG; 277.7±33.6 ng/ml and 44.6±4.4 ng/ml in patients with OTG; 125.2±28.1 ng/ml in patients on ST; 147.2±19.1 ng/ml and 29.8±3.2 ng/ml in the controls. The highest plasma and aqueous humour cortisol levels were found in groups 2 and 1, respectively. Conclusion. Plasma and aqueous humour levels of cortisol appeared to be higher in glaucoma patients than in the controls. Taking into account the fact that plasma cortisol levels are higher in steroid responders, it is recommended that all patients on ST undergo cortisol testing.