Relapses were observed in robins and saw-whet owls infected with L. dubreuili and L. danilewskyi respectively. Parasitemias associated with the relapses were lower than those seen in primary infections except in one robin in which it was unusually high. Gametocytes were seen for 3 months after a relapse. In one bird, in which relapse was noted in 3 consecutive years after infection in the first year, gametocytes were abundant for shorter periods during the second and third years than during the first. Egg laying was not observed in any of these birds although gonadal activity was apparent in those killed after relapses were observed. Schizonts of Leucocytozoon seen in the kidneys of robins, saw-whet owls, and fringilltds several months after infection with L. dubreuili, L. daniiewskyi, and L. fringillmarum, respectively, are probably the source of gametocytes seen in relapses.