Introduction Processing hides and skins and converting them into leathers has long been an important industrial activity. The tannery operation involves a sequence of complex chemical reactions and mechanical processes and has always been associated with odour and pollution. Amongst these, tanning is the fundamental stage, which gives leather its stability and essential character. It is done by chemical reaction between natural tannin, chromium salts or other chemicals and collagen (protein) in the hides. Of world tanneries, 80 – 95 % use chromium salts in their tanning processes. The potential hazards of chromium are complex, for example, chromium in its hexavalent state causes cellular damage via its role as a strong oxidising agent which passes readily through membranes. The globalisation of the leather industry means that all tanners face the same problems of minimising the environmental impact of processing and selling into the global market. Now, more and more Western countries have defined their requirements on chrome-tan leather and its products. Some infant shoes importers are demanding chrome-free leathers. Chrome-free tanning can achieve 80% of the good thermal stability property of the leather produced by the conventional chrome-tanned method and such quality standard is widely accepted by importers in developed countries. In order to enhance the competitiveness and responsiveness of Hong Kong leather industry to market demand on chrome-free leather, the Hong Kong Hide and Leather Traders’ Association and the Hong Kong Productivity Council (HKPC) proposed a project to develop eco-technology for cleaner tanning production. The project work included collection of information on eco production methods for leather production in advanced countries; setting up a pilot chrome-free tanning production system for experimentation of chrome-free processes; compilation of a reference guide containing eco-technology in various stages of leather production and details of the procedures of the chrome-free tanning trials; an abridged version was up-loaded to the web site of the Hong Kong Hide and Leather Traders’ Association; and establishment of a library with collection of project information and trial samples at the Hong Kong Hide & Leather Traders’ Association for easy access by the trade. The information provided inside this guide is of a general nature and is given for reference only. Companies are advised to make their own checks on some of the factors which, depending on their specific situation, may deviate from those that obtained during the project. The Project Team makes no warranty, express or implied, nor assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, equipment, product or process disclosed, nor represents that its use would not infringe privately own rights. Reference herein to any special commercial product, process by trade name, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favouring by the Project Team thereof.