A field experiment was conducted during rabiseason of 2014-2015 at Department of Applied Plant Sci-ence (Horticulture), Baba saheb Bhimrao Ambedkar University, Lucknow-226025 (U.P.) India to find out the effect of different dates of transplanting and mulching on growth, yield and quality of onion (Allium cepa L.) cv. Nasik Red. There were 16 treatments comprising 4 dates of transplanting (15th November, 1st, 15th and 30th December) and 3 mulching (saw dust, rice husk and wheat straw) while, without mulching as control and laid out under two factor RBD with three replications. The study clearly revealed that there were significant effects of all treatments on vegetative growth, yield and quality attributes of onion. Plant height (65.34 cm), number of leaves per plant (8.89), length of leaves (56.07 cm), neck thickness (18.75 mm), yield (5.166 kg/plot and 387.46 q/ha) were found maximum at 1st December planting with wheat straw mulching (T7). The best quality bulb in respect of maximum neck thickness (12.35 mm), basal diameter (13.61.mm), diameter of bulb (54.41 mm polar and 64.15 mm equatorial), length of bulb (65.17 mm), number of scales per bulb (9.24), bulb moisture (85.06 %) T.S.S. (13.84 oBrix), ascorbic acid (10.47 mg/100g), total sugars (10.39 %) etc. were also obtained when mulching was done with wheat straw and transplant-ed on 1st December (T7) followed by T6 (planted on 1st December and mulching with rice husk). The study clearly concluded that i.) mulching is good for production of onion, ii.) late transplanting on 30th December showed very poor performance irrespective of mulching and iii) transplanting on 1st December and mulching with wheat straw was the best combination for getting good quality yield of onion.