Reinforcement corrosion is the most important deterioration mechanism in concrete infrastructure. Chlorides contained in saltwater or de-icing salts penetrate through the concrete cover activating corrosion. When left unattended, corrosion leads to cracking and spalling of concrete cover, reducing the structure's service life. The amount of chlorides required for depassivating the steel is known as critical chloride content or chloride threshold. Because of the importance of the critical chloride content as input for service life prediction models, a precise method for its determination is required. This paper describes a new method for determining critical chloride content in reinforced concrete specimens. Ten reinforced concrete specimens with materials available in the Netherlands were cast, cut, cured, coated, dried and then exposed to chlorides in laboratory conditions. The open circuit potential of the steel reinforcement to an activated titanium electrode was monitored and recorded since the beginning of the exposure period. Specimens were taken from the container seven days after the reinforcement potential dropped more than 150 m V. The chloride content at rebar depth was determined by quantitative Energy Dispersive Spectrometry (EDS). © 2012 Taylor & Francis Group.