Tank bottom sludge from storage tanks of Bombay High crude oil deposited during ten years have been studied. The yield of the sludge is approximately 0.1% wt. of the crude oil through-put. The residue boiling above 500 degrees C amounts to over 50%. The distillate fractions collected at 50 degrees C intervals have been analysed extensively and compared to fractions from whole crude of same boiling range. The sludge distillate are distinctly more paraffinic in nature.