Radiotracer techniques are extensively used for troubleshooting, measuring hydrodynamic parameters and process visualization in industrial systems because of their many advantages over conventional tracer techniques. Most of these techniques are well established, and are routinely used in the industry around the world. This review discusses the general principles of the radiotracer methodology, commonly used applications of radiotracer in the industry, recent advances in the area, and the economic benefits accrued. Each application is illustrated with recently published case studies.