We report on the persistent luminescence of SrAl 2 O 4 : Eu 2+ , Cr 3+ phosphor centered at 760 nm. The phosphor was prepared by sol-gel-combustion method. Persistent luminescence from Cr 3+ lasted for hundreds of seconds, comparable to the long afterglow from Eu 2+ ions in the visible region based on the continuous energy transfer from Eu 2+ ions to Cr 3+ ions. The introduction of Dy 3+ ions into the phosphor further prolonged the afterglow time of Eu 2+ and Cr 3+ ions through the depth control of the charge traps. The optimum doping concentrations for Eu 2+ , Cr 3+ and Dy 3+ were 1%, 2% and 1.5%, respectively.