This article is a review of research and field trials undertaken in Cyprus from 1993 to 1997 with the objective of evaluating the nutritive value of crude olive cake (COC), the by-product remaining after the extraction of olive oil from olives. Ensiling of COC either alone or with other agro-industrial by-products and animal wastes resulted in an extended storage of COC in very good condition. The ensiled by-product, which contained around 10.5 per cent oil (DM basis) was very palatable. When it comprised 15-20 per cent of the whole diet given to growing or lactating ruminants it had a nutritional value ranging from that of barley straw up to that of good quality hay. Ensiled COC was also used for making good quality urea blocks. Based on the experience gained from the present studies it can be concluded that the ensiling technique can be used for long storage of COC, and that ensiled COC can partially replace conventional roughages in diets of mature dry, growing and lactating ruminants.