We constructed a three-dimensional fractal model of the vascular network in a tumour periphery. We model the highly disorganised structure of the neoplastic vasculature by using a high degree of variation in segment properties such as length, diameter and branching angle. The overall appearance of the vascular tree is subjectively similar to that of the disorganised vascular network which encapsulates tumours. The fractal dimension of the model is within the range of clinically measured values.