Atomic force microscopy (AFM) has been employed for the in situ study of the hydrolytic surface erosion of biodegradable polymers within an aqueous environment. These AFM studies reveal the surface polymer morphology to a resolution comparable to vacuum based scanning electron microscopy and demonstrate the influence of a variety of factors including polymer crystallinity and the pH of the aqueous environment on the kinetics of the degradation of bioerodible polymers and their polymer blends. We suggest that this approach can make a substantial contribution to our understanding of polymer degradation within an aqueous environment and will have a major impact on the design of novel bioerodible polymers for exploitation in the medical field.