A cryosurgical instrument, comprising a cryoprobe having ducting through which a compressed cooling fluid, such as a cooling gas, flows, for cooling a least part of the cryoprobe. The ducting has an expansion channel having a channel cross-section that enlarges progressively in the flow, direction over a predetermined length such that the compressed cooling gas gradually decompresses, at least partially, beyond a predetermined length on its flow path through the expansion channel while simultaneously cooling down.
