Fortification of plain and chocolate coated date bars with soy protein isolate (SPI) and dry skim milk (DSM) in different proportions (1.5% SPI + 10.5% DSM; 3.0% SPI + 7.0% DSM and 4.5% SPI + 3.5% DSM) resulted in an increase of protein, fat, fiber, ash, Na, K, Ca, Mg, P, Zn, and all the essential amino acids. The chemical score increased from 48 to a range of 83–95. The in vitro protein digestibility (IVPD) values (77.8–81.8%) and calculated protein efficiency ratios (C-PERs) of the fortified bars (2.40–2.47) were close to the IVPD (90.0%) and C-PER (2.50) of ANRC-casein. In general, sensory evaluation indicated no difference in the control and fortified date bars, which were stored up to six months. 1.5% SPI + 10.5% DSM was the optimum level of supplementation in terms of nutritive benefit.