The effects of calcium, boron and sorbitol on pollen germination in vitro, pollen tube growth on stigma and fruit set in mango cv. Namdokmai were investigated. Both commercial and technical grades of calcium nitrate and boric acid were used in this study, while only purified sorbitol was employed. All chemicals were sprayed onto 5 cm long mango inflorescence. When 50% of the flowers had bloomed, pollen was collected for in vitro observations (Brewbaker ). Pollen tube growth on the stigma was examined by the aniline blue fluorescence method, every 6 hr for 48 hr from 6 hr after hand pollination. Fruit set was examined every 3 days for 45 days afire full bloom. The results showed that the applied chemicals had no effect on pollen germination or pollen tube growth. The percentage of pollen germination in all treatment was 44.52% to 54.16%, and pollen tubes took 24 to 30 hr to reach the stigma ends. Although, calcium. Boron and sorbital did not influence pollen germination and tube growth, they did induce more fruit set in this mango cultivar. Therefore, it is anticipated that these chemicals may exert other effects on the fruit set.