Bioresorbable polymers have been successfully used in clinical applications for many decades. They are those types of polymers that degrade into the human body and often don’t need to be removed out of the body, because their degradation products metabolise and enter the general metabolic pathways. However, there has been an increasing demand for better reliability and degradation control of bioresorbable polymeric devices causing researchers to abandon trial-and-error approaches to model-based methods. The mathematical or computer-based techniques for modelling of the mechanical properties are currently in their infancy or non-existent. This study aims to build a model to express the change in mechanical properties and detecting the degradation distribution within degrading bioresorbable polymers. It consists of three main parts. The first part reviews the literature for the most commonly used bioresorbable polymers and their applications. It also reviews the existing mathematical models for biodegradation. The experimental data of six PLLA films are also reviewed to provide insight into changes in mechanical properties of degrading bioresorbable polymers during hydrolytic degradation. The review shows that the mechanical properties are highly affected by the changes in molecular weight and crystallization. The second part presents a constitutive law for prediction of the elastic moduli, tensile strength and Poisson’s ratio of amorphous and semi-crystalline bioresorbable polymers based on the novel idea of formation cavity and crystal inclusions within degrading bioresorbable polymers. The results of using the constitutive law show that it can fit the experimental data fairly well. The third part presents a vibration-based study that shows the curvature mode shapes can successfully reveal the degradation distribution within, for instance, a simple cantilever beam or a coronary stent. This study also presents a chapter for computer modelling of the degradation behaviour of polyester-based tissue scaffolds using a degradation model developed in the University of Leicester.