The disposal of hazardous wastes, especially organic chemicals, by incineration has been the subject of rapidly increasing interest during the past several years. When such wastes are incinerated, their composition is not the only characteristic that must be determined. Other factors of at least equal importance must be ascertained. These include the varieties and concentrations of any air contaminants that may be emitted during the incineration process. The presence or absence of contaminants shows how well a unit is operating and whether it will perform well enough to meet environmental standards. Research on developing adequate methods of sampling and analysis of the emissions is in progress. These sampling methods are generally applicable not only to incineration but also to processes closely related to incinerations, such as the cofiring of waste in industrial boilers and the burning of contaminated heating oil. Although this article briefly discusses methods for sampling inorganic hazardous compounds, its primary emphasis is on ways of sampling organic compounds likely to be designated as principal organic hazardous constituents (POHCs) for a trial burn.