Pollen tube growth was studied in cvs. Monica, Reyna, Dancy, and Satsuma mandarin (Citrus reticulata unshiu Marc). Pollen tubes were stained with lacmoid and observed with a white light microscope. Lacmoid stained the callose brilliant blue. Pollen grains deposited on the stigma varied from 367 to 4170 among the four cultivars. Pollen germination, however, varied from 1 to 4 %, probably having effects on the ovule fertilization. The pollen load on the stigma of ‘Satsuma,’ both under of open and self-pollination conditions, was low probably due to male sterility. In compatible pollinations the pollen tubes reached the ovary in only 2 days, while in self-pollinated ‘Monica’ and ‘Satsuma’ pollen tubes were not observed in the locules after 8 d. According to the development and number of pollen tubes, cvs. Reyna, Dancy and Satsuma could be good pollenizers for cv. Monica.