A single use lancing device comprising: a housing (10) defining a cavity; a needle assembly (12) comprising a needle (50) and a needle holder (52) and located within the cavity; a release member (16); and a spring (14) arranged to bias the needle assembly in a forward direction relative to the release member; wherein the release member comprises retaining arms (38) and is movable relative to the housing between a primed position in which the retaining arms are arranged to cooperate with the housing to restrain the needle assembly in a primed position, and a deployed position in which the restraining arms are arranged to release the needle assembly to deploy the needle.