Procedures are described for the examination in cross section of thin films by atomic force microscopy (AFM), with reference to anodic films on III-V semiconductors and aluminium as examples of possible applications. It is shown that by preparing cross-sectional surfaces with a diamond knife, the thickness and morphology of anodic films can be disclosed by AFM at a resolution approaching that of transmission electron microscopy, with features such as local nonuniformity of film thickness and layering of the film being revealed.