PURPOSE: The titled ink composition, consisting of polymeric latex particles consisting of a polyurethane polymer containing a dye and an aqueous medium for dispersing the particles, having a high concentration, capable of giving printed dots of improved roundness, and having improved storage stability.

CONSTITUTION: A composition obtained by mixing polymeric latex particles consisting of a polyurethane polymer, containing a dye, preferably a hydrophobic dye, and having a particle diameter of preferably 0.02W0.5μ, and an aqueous medium necessary for dispersing the particles. The polyurethane latex preferably consists of a polyurethane derived from a polyol component which is a prepolymer (mixture) having two or more terminal hydroxyl groups and a molecular weight of 300W20,000 and repeating units of a lower alkyl ether, etc. and an isocyanate component of the formula (R is alkyl, arylene, alkylene bisarylene, etc.).