Bagasse is the fibrous residue remaining after sugarcane or sorghum stalks are crushed to extract their juice and is currently used as a renewable resource in the manufacture of pulp and paper products and building materials.

For each 10 tonnes of sugarcane crushed, a sugar factory produces nearly 3 tonnes of wet bagasse. Since bagasse is a by-product of the cane sugar industry, the quantity of production in each country is in line with the quantity of sugarcane produced.

The high moisture content of bagasse, typically 40% to 50% is detrimental to its use as a fuel. Generally, bagasse is stored prior to further processing. For electricity production, it is stored under moist conditions and the mild exothermic reaction which results from the degradation of residual sugars dries the bagasse pile slightly. For paper pulp production, where it is normally stored wet in order to assist removal of the short pith fibres which impede the paper making process as well as to remove any remaining sugar.

A typical chemical analysis of bagasse might be (on a washed and dried basis):
Cellulose 45%-55%
Hemicellulose 20%-25%
Lignin 18%-24%
Ash 1%-4%
Waxes <1%

Bagasse is an extremely inhomogeneous material comprising around 30%-40% of "pith" fibre which is derived from the core of the plant and is mainly parenchyma material, and "bast", "rind" or "stem" fibre which comprises the balance and is largely derived from sclerenchyma material. This properties make bagasse particularly problematic for paper manufacture and have been the subject of a large body of literature.

Bagasse is used to make insulated disposable food containers, replacing materials such as styrofoam, which are increasingly regarded as environmentally unacceptable. Insulated disposable food containers made of bagasse are commercially available.