Field studies were conducted for two consecutive winter seasons of 2016/2017 and 2017/ 2018 to investigate the effect of mulching; (rice straw and without mulch as control) on bulbs yield, water use efficiency, plant water status and chemical composition of garlic grown under three levels of irrigation (I100 = 100%, I80 = 80% and I60 = 60% of ETC crop evapotranspiration). Bulb yield, water and potassium use efficiency, plant water status (RWC), membrane stability index (MSI) and leaf N and K significantly increased by increasing irrigation levels from I60 to I80 and further to I100. I80 was pronounced on water use efficiency and leaf P, meanwhile I60 was pronounced on leaf total phenolic, flavonoids, anthocyanin, free proline and total free amino acids contents. Garlic plants growth was improved under three levels of irrigation by using rice straw mulch. Results implied that I100 + rice straw, significantly, increased bulbs yield, (RWC), (MSI) and leaf N and K .In addition, I80 + rice straw significantly, increased water use efficiency and leaf P. Howevere, I60 + rice straw significantly, increased leaf total phenolic, flavonoids, anthocyanin, free proline and total free amino acids contents.