Water proof breathable membranes have numerous applications; however, their low wear resistance and low moisture tolerance limit their outdoor use. In this study we reported Ultra-Non-Swelling Microporous Waterproof and Breathable Poly-Urethane membrane through effective dry process; Evaporation induced phase separation method (EIPS). Emulsions and additives of membrane were optimized, to achieve high abrasion resistance and mechanical performance without compromising on hydrophobicity and water vapor transmission. High mechanical and physical stability are attributed to non-swelling behavior and highly crosslinked chains in microporous membrane. With optimized recipe of formulation, UN-MWBP membrane sustained a tensile load of 350 kgf/cm² and abrasion resistance of 15,000 cycles. In addition to such superior mechanical stability, the membrane showed high breathability water vapor transmission 3,000g/m²day and hydrostatic pressure of 3,500mm H2O. Based on such promising results, PU can compete with existing commercial membranes for their facile synthesis, low cost, non-swelling behavior, high stability and commercial scale production. [ABSTRACT FROM AUTHOR]