<p>A method of making cladribine with an increased purity is provided by
a) dissolving crude cladribine in a protic solvent in the presence of a base to form a solution comprising dissolved crude cladribine;
b) maintaining the solution at an elevated temperature so that the solution is homogeneous until the amount of protected or partially protected nucleoside impurities in the solution is reduced to a pre-determined upper limit;
c) cooling the solution of step b) so that crystals of cladribine are formed and isolated.</p>
