Palladium is the active component in several catalytic formulations for environmental technologies, due to its superior performances in the conversion of some hydrocarbons (for example, methane) and halocarbons, and the thermal stability and low volatility of Pd species. The properties and reactivity of Pd-based catalysts in the conversion of methane catalytic combustion for gas turbine applications, reduction of greenhouse gas (methane, N2O) emissions, hydrodehalogenation and oxidative destruction of halocarbons and their applications in the elimination of other pollutants from gaseous emissions are reviewed, with emphasis on the structure-activity relationships, reaction mechanism and sensitivity to poisoning.