Seventy-five patients (114 hands) with mild-to-moderate carpal tunnel syndrome (CTS) were randomized to receive either therapeutic underwater pulsed ultrasound (n=25), sham ultrasound (n=25), or no ultrasound (splint only; n=25). All groups received night splints. The primary outcome was pain assessed by the Visual Analog Scale (VAS). Secondary outcomes included Pain Quality Assessment Scale (PQAS), hand grip strength (HGS), clinical examination tests, and electroneuromyography (ENMG) parameters. Outcomes were assessed at baseline, two weeks, and 12 weeks post-treatment. Overall, the results of the study revealed that the underwater pulsed ultrasound group showed significantly greater improvement in VAS, PQAS, HGS, and ENMG outcomes compared to the other two groups (p<0.001). These findings suggest that therapeutic underwater pulsed ultrasound is an effective, safe, and easy-to-apply conservative treatment for mild-to-moderate CTS.