1,5 Pentanedial, also known as Glutaraldehyde or glutaral is an organic compound with the formula OCH(CH2)3CHO.

This product is used as a disinfectant for sterilization of heat-sensitive equipment and as a laboratory reagent, especially as a fixative. At room temperature it is a pungent colourless oily liquid and is mainly available as an aqueous solution of 50% concentration.

Being non-volatile and bifunctional, glutaraldehyde is often preferred to the less expensive formaldehyde. It reacts with amines, amides, and thiol groups in proteins. A glutaraldehyde solution of 0.1% to 1.0% concentration may be used as a biocide for system disinfection and as a preservative for long term storage. It is a sterilant, killing endospores in addition to many microorganisms and viruses. It is also used for industrial water treatment and as a chemical preservative.