Experimental program and numerical analyses were carried out to investigate the fatigue mechanisms of aluminum drill pipes designed and manufactured in compliance with ISO 15546. Material mechanical properties, including S-N curve, were determined through small-scale tests on specimens cut from actual drill pipes. Full-scale experiments were also performed in laboratory. Initially, the tool-joint assembly procedure was actually performed to monitor the resulting strain/stress level in selected points of the aluminum pipe. Three full-scale aluminum drill pipe specimens were then fatigue tested under combined cyclic bending and constant axial tension. In parallel, a finite element model of the tool-joint region, where two drill pipe specimens failed in the fatigue tests, was developed. The model was first used to reproduce the tool-joint assembly. Then, the physical experiments were simulated numerically in order to obtain the actual stress distribution in this region. Good correlation between full-scale and small-scale fatigue tests was obtained by adjusting the strain/stress levels monitored in the full-scale tests in light of the numerical simulations.Copyright © 2006 by ASME