Th e class ification of oils wi th r esp ect to differe nces in composition is important in t heir use in the manufacture of oil-exte nded butadiene-styr ene rubber. A ra pid chromatographic method of anal ys is has been developed in whic h 2.5-to 3.0-gram samples of oil are desorbed from silica gel into fi ve different fractions by s uccess i ve el u tio n with p entane, benzene, carbon tetrachloride, a nd etha nol as eluents. Six extender-oils were analyzed by t hi s method . Ph ysical properties of t he separated fractions showed marked differences betwee n fractio ns of t he sa m e oil and sim.ilari ties b et ween corresponding fractions of t h e difl'erent o ils. Th e chromatographic separation of extender-oils in to composit iollally different fractio ns provides a method for eval uation of t he eff ect of different componen ts on sp ecifi c properties of t he finished rubber product.