Shortage of available water resources has become a critical problem facing vegetable production in Egypt. So, the aim of this study is to decrease the level of irrigation water: 85 and 70% of full irrigation requirements (FI), versus 100% FI in presence of four compost rates (0, 4.8, 9.6 and 14.4 m3 ha-1). Results show that, deficit irrigation levels caused considerable reductions in many growth parameters and the total yield. But we can save 15% of the water used with an average total yield of 39.15 Mgha-1 and a yield shortage of 14.1% in both seasons. This is an acceptable level of decrease in view of the 36.3 Mgha-1 national average according to the 2017 Egypt’s Agricultural Statistics. The application of compost at different rates increases the growth, quality and quantity of cauliflower at different water deficiency levels. The highest application rate of compost + 100% of FI recorded the highest values in the characteristics of vegetative growth, total yield and NPK content in curd. The treatment 85% of FI + 14.4 m3 compost / ha came in the second rank recording significant differences with all other treatments in both seasons. The results also indicate that the water productivity in the case of 85% FI is significantly equal to the water productivity in case of 100% of FI in both seasons. It is; therefore, concluded that compost applications minimized the negative implications of deficient irrigation on cauliflower production