In situ synthesis of nano-ZnO onto 100% cotton fabrics (terry or woven) by spraying or dipping process resulted in durable antibacterial and UV protection finishes. The nano-sized pore structure of cellulosic fibrils acted as nucleation site for formation of nano-ZnO from the precursors, zinc nitrate and sodium hydroxide. Both the processes resulted in excellent antibacterial activity (>98%) against two representative pathogens, Staphylococcus aureus (Gram-positive) and Klebsiella pneumoniae (Gram-negative) even after 50 wash cycles. The UV protection factor (UPF) was maintained above the minimum accepted level of 50 till 50 wash cycles. Spraying process resulted in 3 times less uptake of nano-ZnO than that of dipping process, without significant reduction in functional properties. The water absorbency and colour of the terry cotton fabrics remain unaffected in the developed processes. (C) 2016 Elsevier B.V. All rights reserved.