A turboshaft engine supporting pylon covered with a porous material and a turboshaft engine/pylon assembly. The pylon supports a turboshaft engine on an aircraft, and includes an outer surface covered at least partially with a porous material to reduce amplitude of acoustic waves leaving the turboshaft engine. The assembly includes a turboshaft engine and a pylon, in which the pylon extends longitudinally from upstream to downstream and includes an upper part for securing to the aircraft, a lower part for securing to the turboshaft engine, and an absorption part extending in an exhaust stream from the turboshaft engine and including an internal absorption part extending inside the turboshaft engine and an external absorption part extending downstream of the turboshaft engine. The outer surface of the upstream end of the external absorption part of the pylon is covered with a porous material to limit noise formation downstream of the engine.