The present invention relates to a refrigerator oil composition which comprises 70 to 98 wt % of a paraffin base oil having a pour point of not more than -35.degree. C., a sulfur content of not more than 50 ppm (parts per million), and a kinematic viscosity at 40.degree. C. of 5 to 500 cSt (centistrokes) and 30 to 2 wt % of a naphthene base oil having a pour point of not more than -35.degree. C., a sulfur content of 0.05 to 1 wt % and a kinematic viscosity at 40.degree. C. of 5 to 500 cSt, and in which the sulfur content is 0.01 to 0.10 wt %.The refrigerator oil composition of the present invention effectively prevents the formation of valve sludge. The refrigerator oil composition of the present invention is also excellent in anti-wear properties. Furthermore the refrigerator oil composition of the present invention is excellent in stability and baking resistance in the condition that is in contact with the refrigerant (Furon) and further is excellent in low temperature solubility. Moreover the refrigerator oil machine oil composition of the present invention contains as a main component a paraffin base oil which is steadily available.