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.