Monophasic Ce3+ and Pr3+ co-doped yttrium aluminum garnet (YAG:Ce3+,Pr3+) nanoparticles with good dispersity and uniform grain sizes in the range of 50–80 nm were prepared by a two-step route, which consisted of a modified co-precipitation preparation of mixed metal hydroxide hydrate intermediates at low temperature of about 40 oC and a subsequent calcination conver-sion of the synthesized intermediates to crystalline nanoparticle products at about 1000 oC. The influences of both the lanthanide ion (Ce3+ and Pr3+) doping concentration and different doping (Ce3+/Pr3+) ratio on the photoluminescence intensity were systematically investigated. The synthesized (Ce0.6Pr0.4)0.04Y2.96Al5O12 nanoparticles were near spherical nanoclusters with good dispersity and uni-form sizes in the range of 50–80 nm for about 85% of the particles. The strongest photoluminescence intensity was observed for the (Ce0.6Pr0.4)0.04Y2.96Al5O12 nanoparticle products.