In order to improve yield and quality of Colombian apple fruits, Thydiazuron (TDZ) and Choline Chloride (CC) biorregulators were evaluated as supposed stimulants of growth and development of 'Princesa', 'Golden Delicious' y 'Gala' varieties in the «La Calera» zone (2650 masl). 50, lOOand 150 mg-L:' of TDZ were sprayed between 30 and 45 days after blooming (dab) and 500, 1000 and 1500 mg-L-' of CC 118 dab, using a completely randomized design for 'Princesa' and 'Golden Delicious' and a completely randomized block design for 'Gala'. TDZ showed chemical thinning and cytokinine activity, decreasing the number and acidity of harvested fruits, but increased mean fruit weight, In 'Gala', TDZ increased the harvested fruit number per tree; with 150 mg-L:' fruit color increased while soluble solids (SS) concentration declined. On the other side, in 'Gala' apples, CC applications decreased fruit number per tree and showed higher mean weights, volume and SS content of fruits, especially with 500 mg-L:'. In 'Golden Delicious' CC produced oblong fruits with higher SS content and lower flesh firrnness.