The present invention relates to an improved process for the purification of tiacumicin B. Specifically, the invention relates to a simplified, optimised process for the purification of tiacumicin B from a fermentation broth, using chromatography techniques. In particular, the invention relates to a method for purifying tiacumicin B which comprises subjecting a liquid containing tiacumicin B to at least one hydrophobic interaction chromatography step.The process according to the invention is simpler than the processes according to the prior art, and can easily be used on a large scale for commercial production.