A brief overview is given of the sources, characteristics, and toxic constituents of municipal solid wastes. Several methods are presented for handling, treating, and disposal of solid wastes. Monitoring the landfill site is necessary; there has been a trend to recognize that municipal solid wastes may be hazardous and to provide separate secure handling, treatment, and disposal for their dangerous constituents. Under current state and Federal regulations, permits are being required to assure that proper handling of conventional solid wastes and more hazardous constituents are carefully managed.