Corrosion-resistant weld overlays are often used to improve the service life of components made with an otherwise corrosion-prone material such as carbon or low alloy steels. One of the major concerns in arc welding overlay is iron dilution consequently influencing the corrosion performance of the weld overlays.Corrosion tests have been carried out to determine the effect of iron content on localised corrosion resistance of Ni-Cr-Mo alloy weld overlays in chloride ions containing environments. A range of iron contents i.e. 5 – 50% were examined using test coupons extracted from weld overlays. The iron content range was achieved by optimising the welding parameters where the weld overlays were deposited by gas tungsten arc welding (GTAW) (also known as tungsten inert gas welding TIG) and gas metal arc welding (GMAW) (also known as manual metal inert gas MIG) processes. Pitting corrosion potentials were determined in acidified 10%w/v NaCl solution at 25°C using potentiodynamic polarisation curve measurements. Critical pitting temperatures (CPTs) were determined by standards ASTM G150 in 1M NaCl and ASTM G48 Method C in 6%FeCl3 +1%HCl. Critical crevice temperatures (CCTs) were determined by ASTM G48 Method D in 6%FeCl3 +1%HCl. Pitting and crevice corrosion tests were also carried out in aerated artificial seawater in a range of temperatures from 25 to 70°C. The results showed that localised corrosion resistance of the weld overlays behaved very similarly with the iron content ranged between 5 and 15% and the resistance reduced significantly as the iron content increased to above 30% in the weld overlay. The results support a relaxation on maximum iron dilution of 5% which is currently used in industries.Key words: weld overlay iron content pitting corrosion potential critical pitting temperature (CPT) critical crevice temperature (CCT).