A new method for determination of urinary O-hydroxylysyl-glycosides (OHLG) is described. Human urine was extracted with 2 volumes of ethanol, followed by gel-filtration on a column of Sephadex G-10. The presence of OHLG in the alkaline hydrolyzate of the fraction obtained by gel-filtration was proved by paper chromatography and by liquid chromatography. The alkaline hydrolyzate was subjected to Dowex 50 X4 (H+ form) column chromatography, and OHLG were eluted with 1.5N NH4OH. Content of OHLG in the eluate was determined by the anthrone-H2SO4 method in terms of hexose. Excretion rate of OHLG in urine of adults was shown to be 20 mumoles in terms of hexose per day.