Abstract: A drill pipe coupling includes a coupling member (2) having an unthreaded central section (13) with a cylindrical bore (26) therein and an outer shoulder (11,12) on each side thereof. Adjoining the shoulders are respective conical external threads for threading into an internal correspondingly threaded upset head section of a drill pipe formed as a bell elements and including end surfaces (9,10). The drill pipe has an undeformed cylindrical bore (14) connected to the threaded upset head. The drill pipe end surfaces (9,10) sealingly abut the outer shoulders (11,12) of the central section (13) when the pipes are joined together. The drill pipe has an intermediate section (16) adjoining the cylindrical bore (14) and has an inside diameter which decreases in the direction toward the threaded section (5, 6).