Histamine is implicated in several reproductive functions. Correlation between histamine metabolism and sex hormones has been a matter of interest for many years. Urinary histamine excretion has been studied under various experimental conditions in different species. In man it was reported, that the urinary excretion of histamine and/or methylhistamine in women was correlated to the excretion of oestrogen. Very little is known about the condition in man with intersex. The case reported here shows that histamine and methylhistamine excretion in urine in a patient with testicular feminizing syndrome is unaffected by castration.