Field experiments were initiated during 2017 and 2018 seasons at the Experimental Farm of Sakha Research Station, Kafr El-Sheikh, Egypt to explore the effects of different irrigation regimes and plant spacing on growth, grain yield and water productivity of Giza 179 rice cultivar. The experiments were laid out in a strip-plot design with three replications. Three irrigation treatments namely, continuous flooding (CF), irrigation every 6 (6D) and 9 days (9D) were located in the horizontal plots. However, the vertical plots were occupied by four plant spacing i.e. 15 x 20, 20 x 20, 25 x 20 and 30 x 20 cm. The main results revealed growth, grain yield and it components were significantly increased at CF and 6D compared to 9D treatment. The close spacing (15 x 20 or 20 x 20 cm) registered higher values of growth and grain yield than of wider one (30 x 20 cm). The density response gradually increased with prolonging irrigation from CF to 6D and recorded the maximum response to narrow spacing 9D treatment. CF recorded the highest amount of water usage, while the lowest amount was received by 9D treatment. Irrigation every 6 days gave similar grain yield to CF with less amount of water and gave reasonable water productivity. Generally, it could be concluded that, under the same conditions, using irrigation every 6 days with the close spacing (15 x 20 or 20 x 20 cm) leads to high values of growth, grain yield, and water productivity for Giza 179 cultivar.