Industrial activities inevitably result in solid, liquid and gaseous wastes that are unwanted. If allowed to accumulate in the environment, or if dumped indiscriminately into rivers and other bodies of water, unacceptable environmental problems would result. Governments in different countries institute legislation which regulates the handling of wastes, including those resulting from the industry. Environmental protection and related agencies in those countries develop and enforce environmental laws. The activities of industrial microorganisms usually occur in large volumes of water; the resulting wastes are therefore transported in aqueous medium. Wastewater disposal constitutes a peculiar branch of industrial microbiology. In this chapter, topics touched upon include methods for the determination of organic matter content in wastewaters, dissolved oxygen (DO), biochemical oxygen demand (BOD), permanganate value (PV), chemical oxygen demand (COD), total organic carbon (TOC), total suspended solids (TSS), volatile suspended solids (VSS), systems for the treatment of wastes, aerobic breakdown of raw wastewaters, treatment of the sludge, anaerobic breakdown of sludge, and wastewater disposal in the pharmaceutical industry.