To provide a waste liquid composition for incineration which hardly fluctuates the furnace temperature of an incinerator at the time of incineration, a method for adjusting the composition, and a method for efficiently incinerating wastes.

A waste liquid composition for incineration is composed at least of one kind of waste and thrown in an incinerator for incineration together with another material while the material is burnt in the incinerator. The calorific value of the composition is adjusted to such a low value as -100 kcal/kg to 2,500 kcal/kg. It is desirable to adjust the calorific value of the composition to the above-mentioned low value without adding any combustion improver.