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The phosphate/primer interface has been identified as the site of attack in several corrosion studies. It is expected that all aspects of the pretreatment process including oiling, cleaning, and phosphating affect corrosion performance. The extent of the effects is likely related to substrate type. An alloy coated material such as galvanneal (with its range of surface morphologies) could be particularly susceptible to variations in the pretreatment process. This paper reports a study examining the relationship of galvanneal surface morphology to phosphatability and resulting corrosion performance. Examination of phosphate crystal morphology, coverage, alkaline stability, and coating weight as a function of phosphate application mode and bath chemistry for conventional automotive phosphates was completed in the study. Electrochemical methods were used to evaluate phosphate porosity and to predict phosphate stability.