P H o T O T H ~. g A V Y is effective in lowering the serum bi l i rubln concentra t ion in many low-bir th-weight infants wi th physiologic or id iopa th ic j a u n d i c e ? -~ Serum bi l i rubin values may be decreased in both Caucas ian and Negro newborn in fan t sJ Pho to the rapy has also been repor ted to lower serum bi l i rubin concentrat ions in hemolyt ic disease due to A B O incompat ibi l i ty . 7 T h e purpose of this repor t is to call attent ion to a group of newborn infants who d id not show a significant clinical response to pho to the rapy and were therefore considered pho to the rapy failures. As this was no t a control led study, r igid cr i ter ia were not used to de te rmine the ind ica t ion for photo therapy. I n general , the decision was based on the clinical history, serum bi l i rubin values above 12 rag. pe r 100 ml., and ind iv idua l evaluat ion of each patient, F ive infants, born a t Cook County Hospi ta l , were exposed to eight 40 wa t t b lue fluorescent lights, 5 and 3 infants, born at Univers i ty of Ill inois Hospi ta l , were exposed to eight 20 wa t t Vi ta l i te f luorescent lights. Pho to the rapy was in t e rmi t t en t as previously repor ted. 5