Monodisperse blue-colored poly(styrene-co-acrylic acid) latices were successfully prepared by seeded emulsion polymerization. Blue-colored latices with carboxyl anionic charge on the surface were synthesized at the second stage with the introduction of Blue 606 dye, acrylic acid, and 0.21 ${mu}m$-polystyrene seed. All the blue-colored latices synthesized in this study were in the size range of 0.25~0.42 ${mu}m$ and all uniform with less than 1.01 in PSD. The particle size increased with the addition of acrylic acid being delayed and colloidally stable latices were obtained over 30 min after its addition. The blue-colored latex with 20 wt% acrylic acid showed -145 mV of zeta-potential and $-9.4{ imes}10^{-6};cm^2/Vs$ of electrophoretic mobility, and with 25 wt% of DVB showed high $T_g$ at 396.7 K.