We present a novel algorithmic approach to find a proper vertex colouring of a graph with d colours, if it exists. We associate a d-dimensional quantum system with each vertex and the initial state is a mixture of all possible colourings, from which we obtain a random proper colouring of the graph by measurements. The nondeterministic nature of the quantum measurement is tackled by a reset operation, which can revert the effect of unwanted projections. As in the classical case, we find that the runtime scales exponentially with the number of vertices. However, we provide numerical evidence that the average runtime for random graphs scales polynomially in the number of edges.A proper vertex colouring, often simply called a colouring of a graph, is an assignment of colours to vertices of a graph g, such that no adjacent vertices have the same colour [1]. A colouring that uses d different colours is called a d-colouring and a graph for which a d-colouring exists is called dcolourable. The chromatic number χ(g) is the smallest number d such that g is d-colourable. See Figure 1 for a graph with chromatic number 3.It is hard to compute χ(g). In fact finding χ(g) is one of Karp's 21 famous 3,4,5], which means that every problem in NP can be solved by calling an oracle version of the graph colouring a polynomial number of times. And even when considering only planar graphs with vertex degree at most four and d = 3 different colours the problem remains NPcomplete [6]. Various problems of practical significance are naturally linked to the graph colouring problem. This includes planning and scheduling problems as they occur in industrial settings like manufacturing [7] and cost optimization [8].In the present paper we introduce an algorithm that finds a graph colouring on a quantum com-