The article presents the results of experimental research into the electric and optical characteristics of a discharge electrodeless UV LP lamp. Induction discharge of the transformer type was excited in the lamp using a mixture of mercury vapour (10–2 mm Hg) with inert gases Ne (60 %) + Ar (40 %) (1 mm Hg) at a frequency of 225 kHz in a closed tubular envelope of quartz glass of 53 mm diameter and 760 mm length. With increase of the lamp power from 80 to 170 W, power losses in its inductor decreased from 45 to 24 W, and energy efficiency of the lamp discharge part in the mercury line of 253.7 nm increased from 17 to 29 %.