In this article, an optimization procedure for the placement of integrated circuits (ICs) for reduced radio-frequency interference (RFI) in mobile devices is presented. The concept of a power conversion factor (PCF) is introduced to quantify the near-field radiation of ICs based on near-field measurement techniques. For PCF extraction, equivalent source antennas are designed to represent the radiation chracteristics of ICs. In addition, the concept of a power transfer function (PTF) is also introduced to characterize the near-field propagation from RFI noise sources to the built-in antennas in mobile devices. From the combination of the PCFs and the PTFs, a spatial near-field specification of ICs for reduced RFI is proposed. Based on the proposed specification, the application example of an optimized IC placement in mobile platform design is presented.