Abstract: Field experiments were conducted to find out the effect of organic manures on the nutrient uptake and soil fertility of cassava at Veterinary College and Research Institute Farm, Namakkal during 2001 and 2002. The popular hybrid of cassava H 226 was tried as test crop. Six organic manurial treatments viz., FYM (25 t ha-1), Poultry manure (10 t ha-1), composted poultry manure (10 t ha-1), FYM (12.5 t ha-1) +poultry manure (5 t ha-1), FYM (12.5 t ha-1)+composted poultry manure (5 t ha-1) along with control (no organic manure) were tried. The study revealed that all the organic manurial treatments had higher uptake of all the nutrients, higher tuber yield and post harvest soil nutrients than control. Composted poultry manure either alone or with FYM recorded higher nutrient uptake, tuber yield and post harvest soil nutrients depleting the soil nutrients, the least. A slightly positive N balance was associated with CPM while all the other manurial treatments had slightly negative balance.