A low-pressure mercury vapor discharge lamp (1) has a discharge vessel (3) enclosing, in a gastight manner, a discharge space provided with a filling of mercury and a rare gas. The discharge vessel (3) comprises means for maintaining an electric discharge in the discharge space. A portion of the surface (15) of the discharge vessel (3) facing the discharge space is provided with a protective layer (16) comprising yttrium oxide or aluminum oxide and further comprises a borate and/or a phosphate of an alkaline earth metal and/or of scandium, yttrium, or a further rare earth metal. Preferably, the alkaline earth metal is calcium, strontium, and/or barium. Preferably, the further rare earth metal is lanthanum, cerium, and/or gadolinium. The lamp according to the invention has a comparatively low mercury consumption.