This study evaluated the corrosion effect of stainless steel and galvanized steel exposed to water emulsified diesel, diesel and palm biodiesel under laboratory immersion carried out at 25 � for 1200 h. The effect of stainless steel and galvanized steel exposed to emulsified diesel at 25 � for 240, 480, 720, 960 and 1200 h was also evaluated. Emulsified diesel consists of 5 vol water, 1.5 vol Span 80, 1.5 vol Tween 80 and 92 vol diesel was prepared using high shear stirrer for 20 min at 3500 revolutions/min. Corrosion rate, surface morphology, elemental composition, optical microscopy, mean droplet diameter, dispersity index, density, viscosity, water content and total acid number were performed. Stainless steel and galvanized steel immersed in emulsified diesel had 1.1 and 8.5 times higher corrosion rate than in diesel, respectively. Stainless steel had 0.5 times lower corrosion rate when exposed to emulsified diesel than biodiesel. While, galvanized steel had 3.5 times higher corrosion rate exposed to emulsified diesel than biodiesel. 114 and 97 reduction in corrosion rate experienced by stainless steel and galvanized steel exposed to emulsified diesel, respectively, between 240 and 1200 h of immersion duration. Higher acidity of emulsified diesel than diesel due to the presence of Span 80 and Tween 80 is suggested to have influenced the higher corrosion for stainless steel and galvanized steel in emulsified diesel than diesel. Considering lower corrosion rate of stainless steel in emulsified diesel than biodiesel, coupled with the acceptance of biodiesel for use in blended form with diesel, this suggest that the corrosion level of stainless steel in emulsified diesel is within acceptable level. More research works exploring possibility of preparing stable and less acidic emulsified diesel and its effects towards metals are required to establish the compatibility of emulsified diesel with fuel delivery metals. © 2023 Elsevier Ltd