The document is a practice guide for measurement of low impedances using RLC bridges and electrochemical impedance spectrometers. The first part covers general problems related to the measurement of low impedances. It shows various impedance standard types, proper connections to the bridge/EIS meter and corrections that can be applied to improve uncertainty of measurement. This guide has no ambition to cover entire impedance measurement problematic. To this end, the reader is referred to textbooks and comprehensive handbooks of impedance meters. It rather focuses on problems that are typical for low impedance measurements.