Assessing the regenerate strength in distraction osteogenesis is crucial for clinical treatment. Several methods have been used to achieve this, including plain radiography, digital radiography, quantitative computed tomography, dual energy xray absorptiometry, and ultrasound. The aim of the current study was to investigate the use of ultrasound in monitoring regenerate formation and to correlate this to biomechanical testing results. An osteotomy was done on the tibia of 30 Yucatan micropigs and an Ilizarov-type half-ring external fixator was mounted. After a 5-day latency period, the tibias were distracted for 10 days and then left to consolidate for 10 days. Seven ultrasound examinations were done during Day 15 through Day 25. After sacrifice, the bone mineral density was measured using quantitative computed tomography. Maximum load and torsional stiffness were measured and correlated with ultrasound measurements and bone mineral density. The ultrasound penetration depth and the bone mineral density correlated closely with torsional stiffness. Ultrasound can be a noninvasive predictor of bone regenerate strength in the early phase of distraction osteogenesis, which may reduce the need for radiographs.