Microwave power measurements are used to support almost every every segment of the microwave electronics industry. It is very important for these measurements to be as accurate as possible. Recently we have found several different problems that affect microwave power measurements. One of the main problems is leakage of the microwave energy through the microwave power sensors. This paper will explore some of the effects this leakage energy has on different parts of microwave power measurement systems and the power measurement process and possible ways of handling the errors that are associated with this energy.