Hyponatraemia is commonly reported in chronic alcoholic patients. However, the underlying pathogenetic mechanisms are not well delineated. In the current study, we analysed the possible pathophysiological mechanisms of hyponatraemia in a group of alcoholic patients (n = 127) admitted to our hospital for causes related to alcohol misuse. Hyponatraemia (serum sodium <134 mmol/l) was found in 22 patients (17.3%). The most common cause of hyponatraemia in our cohort was hypovolaemia (12 patients); pseudohyponatraemia was diagnosed in six patients with alcohol-induced severe hypertriglyceridaemia. It is of interest that two patients fulfilled the criteria of the so-called 'beer potomania' syndrome, while in two others, hyponatraemia was due to reset osmostat or to cerebral salt wasting syndrome, not previously described in alcoholic patients. It is concluded that hyponatraemia is a frequently observed electrolyte disorder in hospitalized alcoholic patients and is related to various pathophysiological mechanisms.