The European Community legislation established a pig grading regulation in order to make the market more transparent and to guarantee producers fair payment. In Spain it does not exist a grading system for payment as in France or Holland that stimulate the production of a defined kind of carcass. Values of reference to compare results obtained by farmers with those of companies, regions or countries are not published. This works analyse the quality carcass, characteristics obtained in farms of a co‑operative from Navarra. A total of 22.635 carcass were classified by using "Fat‑O‑Meater" in a slaughter during 1997 and 1998. The heterogeneity in carcass quality (thickness of backfat, thickness of muscle and estimated percentage of lean meat) and some influencing factors (year, farm, carcass weight) were analysed. In a small subsample electrical conductivity was also measured as a criteria of meat quality. Results shown regular carcass and meat quality characteristics (55% of lean meat, 17 mm of thickness of backfat, 53 mm of thickness of muscle, 6µS of electrical conductivity) and a high heterogeneity mainly among carcass and for the thickness of backfat. There was not a clear relationship between meat and carcass quality, therefore results indicated that meat quality was higher in carcass with less lean meat content.