Adhesion force mapping using atomic force microscopy has been used to investigate a phase-separated blend of poly(methyl methacrylate) (PMMA) and poly(dodecyl methacrylate) (PDDMA). Comparison of the results from the blend with those from the pure constituent polymers showed that force mapping could identify PMMA- and PDDMA-rich areas in the blend. The adhesion maps produced were deconvoluted from sample topography and contrasted with data obtained from contact angle goniometry.