Abstract: A lubricating oil composition for the internal combustion engine comprising (i) a mineral lubricating base oil, a synthetic lubricating base oil or a mixture thereof, (ii) a specified amount of at least one alkyl molybdenum dithiophosphate having secondary alkyl ##STR1## wherein R.sub.1 is a secondary alkyl group having from 5 to 8 carbon atoms, X is O or S which may be the same or different, and the O/S ratio is from 3/1 to 1/3, and (iii) a specified amount of at least one alkyl zinc dithiophosphate having a primary alkyl group represented by the formula (II) ##STR2## wherein R.sub.2 and R.sub.3 are each a primary alkyl group having from 3 to 8 carbon atoms which may be the same or different, and (iv) an additive of the lubricating oil containing the above components (b) and (c) for use in internal combustion engines.

Abstract: A process for producing a lubricant base oil with low pour point and high aromaticity from a feedstock oil which is either a distillate fraction boiling at 250.degree. C. or above that is obtained from a paraffin base or mixed base crude or a deasphalted oil obtained from a vacuum distillation residual oil of said crude, and process comprising:(a) the step of bringing said feedstock oil into contact with a hydrofining catalyst in the presence of hydrogen and recovering a hydrofined oil;(b) the step of dewaxing said hydrofined oil and recovering the dewaxed oil;(c) the step of subjecting said dewaxed oil to extraction with a solvent having selective affinity for aromatic hydrocarbons so as to separate the feed into the raffinate portion and the extract portion, and removing the solvent from said extract portion to obtain an extract oil; and(d) the step of treating said extract oil by means of contact with a solid adsorbent or sulfuric acid.