Abstract:The study was conducted in net house conditions of fruit Nursery block of Department of Fruit Science, Dr. Y. S. Parmar University of Horticulture and Forestry Nauni, Solan H.P. during 2012-2013 in order to evaluate the effect of size of cuttings (length and diameter) on rooting in cuttings of apple clonal rootstock Merton 793. Cuttings of length (L) viz. 15 cm, 25 cm, 35 cm, 45 cm and diameter ranges (D) viz. 0.75 cm -1.00 cm, 1.00 cm -1.25 cm, 1.25 -1.50 cm were taken. The experiment was laid out in randomized block design (factorial). The cuttings were treated with 2500 ppm IBA (Indole -3 -butyric acid) as quick dip (10 -15 seconds) before planting. The results revealed that the cuttings with treatment combination of length (35 cm) and diameter (1.25 cm -1.50 cm) recorded the highest rooting of cuttings (65 %), number of primary roots (5.00), length of primary roots (28.43 cm), diameter of primary roots (3.25 mm), fresh weight of roots (3.67 g) and dry weight of roots (2.59 g). Hence it is concluded that cuttings of length of 35 cm and diameter of 1.25 cm to 1.50 cm was most suitable for propagation. However, the cuttings of shorter length and diameter, are also able to result in rooting with lower success, therefore, these cuttings would be helpful in case of scarce availability of propagating material.