The present study aimed to evaluating the yield and water use efficiency (WUE) of intercropping soybean and maize under deficit irrigation and carried out at the experimental farm of the Faculty of Agriculture, Fayoum University, Egypt in 2013 and 2014. The experimental layout was distributed in split plot arrangement in randomized complete block design with three replicates. The irrigation treatments included three mainly (I1 =100, I2 =85 and I3 =70% of ETo) with three cropping systems (sole soybean, sole maize and soybean/ maize intercropping) were occupied the main and sub.plots, respectively. Surface irrigation using spiles was used and crops were planted in rows within each plots (10.5 m2 for each).Data obtained showed that plant leaf relative water content, chlorophyll fluorescence and performance index were significantly decreased with deficit irrigation and grater values were observed with intercropping in comparison with sole system. Under intercropped system and both sole maize and soybean, the maximum values of grain yield (GY) was obtained when plants were irrigated with I1. The results demonstrated that intercropping soybean with maize significantly reduced soybean and maize crop yields in both seasons, however the total intercropped yield was greater than that of sole crops. Land equivalent ratios (LER) of all intercrops were greater than unity; denoting that higher productivity per unit area was obtained by growing maize and soybean crops together than by growing them sole. The maximum values of LER were recorded with crops irrigated using (I1) treatment (1.47 and 1.45), whereas the lowest LER values were obtained when crops were irrigated with I3 treatment (1.29 and 1.28). The greatest WUE was found under soybean/maize intercropping and irrigated with I1 treatment. However, WUE was relatively low under irrigation with I3. Based on the results of the present work, it could be concluded that soybean/maize intercropping provide to be better.