The bundle of His is a bundle of heart muscle cells specialized for electrical conduction that transmits the electrical impulses from the AV node to the cells of the ventricles, causing cardiac muscles in the ventricles to contract.

These specialized muscle fibres in the heart was named after the Swiss cardiologist Wilhelm His, Jr., who discovered it in 1893.

It is an important part of the electrical conduction system of the heart.

Dysfunction of the bundle of His leads to heart block, usually leading to a slowing of the heart rate.