The Scanning Electron Microscope (SEM) has been used to study the adhesion of red oxide primer on selected substrates. The substrates are stainless steel, mild steel, galvanized steel and aluminium. Twenty (20 No) specimens were prepared from the four different substrate metals and examined metallographically, after coating them with red oxide primer using different methods of application. Results showed varying degrees of adherence. The red oxide primer was able to form bonds with the different substrate metals, especially with the well cleaned, primed and subsequently painted stainless steel specimen.