The bone surgery often makes use of implants to sustain and fix the bones during the healing phase. Commonly used implants require a surgical procedure to be removed after bone healing, so there is a strong demand for a new typology of bio-absorbable implants. Magnesium and its alloys are promising materials for orthopedic self-degrading implants, mainly if they are protected by a thin coating. The design of Mg-based implants cannot disregard the adoption of a simple measurement procedure for assessing and monitoring the corrosion evolution in environments simulating the body fluids. This paper describes a measuring approach for the corrosion behavior assessment of different Mg-based alloys uncoated and coated with innovative surface treatments, based on Electrochemical Impedance Spectroscopy measurements.