Factor Rhesus, wanda kuma aka sani da Rh factor, furotin ne da ake samu a saman jajayen ƙwayoyin jini. Sunan ta ne bayan Rhesus macaque, nau'in biri wanda aka fara gano furotin a cikinsa. Kasancewa ko rashi na Rhesus factor yana ƙayyade rukunin jinin mutum na Rh, wanda shine ko dai Rh-positive (protein yana nan) ko Rh-negative (protein ba ya nan). Rh factor yana da mahimmanci wajen ƙarin jini da kuma lokacin daukar ciki, saboda rashin daidaituwa na Rh tsakanin uwa da tayin na iya haifar da matsalolin lafiya.