A series of N(4-chloro-3-sulfamoylbenzamido) derivatives (6 a-c, 10, 11, 12), structurally related to indapamide and isoindapamide, were synthesized and tested for their diuretic and saluretic activity. In addition, the antihypertensive activity of the most interesting term trans 6a was studied on spontaneously hypertensive rats. All tested compounds with the exception of 10 showed diuretic activity comparable to or higher (trans 6 a) than that of indapamide, taken as reference drug. The antihypertensive activity of trans 6 a was comparable to that of indapamide in potency, but its onset of action was slower.