In this chapter, the petrochemical industrial wastes and their valorization techniques are discussed in a systematic manner. Wastes from the petroleum industry are classified into liquid and solid wastes. Liquid wastes are mainly categorized into oily sludge and waste lube oil. Solid wastes from the petrochemical industry are spent catalysts from the different units of refineries and the solid components of oily sludges. Valorization of liquid wastes can be achieved by recovering oil from the oily sludges and producing base oil from the waste lube oil respectively. Methods to recover the oil from oily sludges and base oil recovery from used lubricant are described. Valorization of solid wastes from petroleum industries can be done by recovering metals from the waste, using the solid waste as a precursor in other processes, and as an additive in cement and ceramics manufacturing, etc.