This investigation was carried out during two successive summer seasons of 2014 and 2015, at Vegetable Private Farm at Fakous District, Sharkia Governorate, under sandy soil conditions with drip irrigation system (GR dripper at 30 cm space). It aims to study the effect of transplant tray cell size and plant spacings within-row in open filed on growth, yield and fruit quality of Hanny F1 hybrid muskmelon. The obtained results showed that both root and stem length, stem diameter and number of leaves/transplant, fresh and dry weight of root, shoots and total weight/transplant at transplanting (25 days after seed sowing) were significantly increased when transplants were produced in trays with larger cell size (40 cm3) in both seasons. While using smaller cell size (28 cm3) gave lower values of transplant vegetative growth and fresh and dry weight in both seasons. Planting muskmelon transplants at 60 cm on one side of the dripper line increased plant length, number of leaves/ plant, root length, number of fruits/plant and yield/plant when transplants were produced in trays with bigger cell size (40 cm3). Planting at 45 cm on two sides of the dripper line increased number of main branches/plant and average fruit weight when transplants produced in trays with bigger cell size (40 cm3), whereas planting at 45 cm on one side of the dripper line increased number of secondary branches/ plant, dry weight of roots, shoots and total dry weight/plant when transplants were produced in trays with bigger cell size (40 cm3). Planting muskmelon transplants produced in tray with cell size of 40 cm3 at 45 and 60 cm on two sides of the dripper line gave the highest values of marketable, total yield/fad., as well as total carbohydrates in fruits, total sugars, TSS and TSS/acid ratio contents in both seasons,whereas planting those obtained from trays with 28 cm3 cell size at both 45 and 60 cm on two sides of the dripper line gave the highest values of total fibers in fruits. Planting at 45 cm on one side of the dripper line increased firmness in fruits when transplants were produced in tray with smaller cell size.