Corrosion testing and monitoring are powerful tools in the fight to control corrosion. This chapter provides a general overview of three major categories of corrosion tests, namely laboratory tests, pilot-plant tests, and field tests. It begins with brief sections describing the purposes of corrosion tests, the logical steps in a test program, and the preparation and cleaning of test specimens. The focus then moves on to discuss the types and applications of these test categories and the associated evaluation procedures. Excluding electrochemical tests which are addressed separately in this chapter, the other laboratory tests covered under this category are simulated atmosphere tests, salt-spray tests, and immersion tests. Only corrosion testing in the atmosphere is discussed in the section on field tests. Corrosion monitoring techniques are finally considered, covering the characteristics of corrosion monitoring techniques, the factors to be considered in selecting a corrosion-monitoring method, and the strategies in corrosion monitoring.