To provide a polymer mixture useful as a viscosity improver for lubricating oil.

This mixture includes (A): a copolymer containing about 70 to about 79 wt.% of units derived from ethylene, and having (a) Mw measured by gel permeation chromatography employing polystyrene standard ranging from about 50,000 up to less than 130,000, and/or (f) SSI≤18; (b) density (D) ranging from about 845 to about 895 kg/m³; (c) the value of formula (1): Mw/Mn is less than 3; (d) melting point (Tm) measured by differential scanning calorimeter ranging from about 15°C to about 60°C; and (e) degree of crystallinity ≥15%; and (B) an amorphous polymer having Mw ranging from about 130,000 to about 1,000,000, and having degree of crystallinity, ≤5%.