With electronic systems becoming more complex, the electromagnetic compatibility (EMC) behavior of cable and connector assemblies is becoming more important. A shield is a metallic partition placed between two regions of space used to control the propagation of electromagnetic field from one region to the other. Shielding is necessary to prevent emission of electromagnetic waves from the devices that could affect electronics, and also to protect cables from external electromagnetic interference (EMI). The only way to prove shield efficiency is to measure the impact of shield on propagation of electromagnetic field trough it. However, because the practical testing needs are not always obvious and often cannot be defined in certain and unique terms the cable shielding industry has come up with a great number of measurement techniques and procedures, hardware designs, literature descriptions, test standards, guides and practices. By far, one of the most familiar and often measured and used characteristic of the shield is transfer impedance which is useful measure of the screening properties of the cable/connector assembly. For practical use any characteristic must be capable of evaluation and measurement, even if only qualitatively, and the shield transfer function is no exception. In this work it has been tried to clarify the question of what is transfer impedance and how to numerically calculate it. The proof of transfer impedance numerical calculation was given trough measuring.