PURPOSE: To obtain the subject pigment composition which has superior storage stability and is useful for a magnetic recording medium by incorporating a specific silane modified phosphate ester and a magnetic metal pigment in a specific proportion.

CONSTITUTION: The objective composition contains (A) 2-15 pts.(wt.) of a reaction product of (i) a reaction body selected from the mixture of silyl alkyl esters of phosphorus of formula I (Me is methyl; Q is OMe, a 1-4C alkyl; R' is a 3-8C bivalent hydrocarbon; R is a 1-3C alkyl) or an organic phosphate ester of formula II and a haloalkyl functional silane represented as R-R'Si(OR)3 and (ii) 2-15 pts.(wt.) of a reaction product with an organic halide of formula III ((n) is 8 to 22), and (B) 100 pts.(wt.) magnetic metal pigment.