Motor unit number estimation (MUNE) has been used to track motor unit attrition. Studies have used the modified multiple-point stimulation (MPS) technique, collecting three surface motor unit action potentials (sMUAPs) from 3 sites to calculate MUNE. Factoring additional sMUAPs should theoretically improve reproducibility, but the optimal number has not been defined. We evaluated the effect of increased sMUAP sampling on test-retest reproducibility of the modified MPS MUNE technique and found that MUNE reproducibility increased with additional sampling. Muscle Nerve, 2010.