This paper examines fine grinding techniques in current use in the pharmaceutical industry. Experimental results are given for fine grinding of vitamin C, chosen as a model substance representative of pharmaceutical products, using eight different grinding mills chosen amongst those in current use in the pharmaceutical industry. The results are evaluated in term of product quality expressed as particle size and distribution and also in terms of operating criteria applicable in the pharmaceutical industry such as ease of setting up, ease of cleaning, and investment cost. The main conclusion reinforces and quantifies current practice of using pancake mills that are preferred for ultra fine grinding as they are simple to use, can treat high feed rates and are easy to clean. (C) 2004 Elsevier B.V. All rights reserved.