Therapeutic ultrasound is a physical modality which is constantly expanding range of indications. Analgesic effect of ultrasound is still under discussion. Regardless the extensive application of pulsed ultrasound of low intensity, continuous ultrasound has a better analgesis effect, which is explained by its mechanism of action.The main research objective of this study was to determine the effect of continuous ultrasound to pain caused by degenerative diseases of the musculoskeletal system in the intensity and duration of ultrasound treatment. Other objectives are entailed determining the correlation between the degree of pain reduction with: location of pain, age, gender and body mass index (BMI).The study included 68 patients with chronic pain localized in the region of the spine or major joints of the extremities, depending on the localization of the degenerative changes. Patients are divided into two groups. The first group was treated with 10 applications of continuous ultrasound with frequency of 1 MHz, intensity 0.4 W/cm2 for 8 minutes, and the other group with 10 applications of ultrasound with frequency of 1 MHz, intensity 0.8 W/cm 2 for 4 minutes.Pain intensity was assessed before and after ultrasound therapy performed by subjective visual analogue scale (VAS) for pain, numbered from 0-10, where 0 is the rating for the state of no pain, and 10 grades for severe pain. The average VAS improvement in the first group was 3.97, and 4.74 in second one. The results of F (1.66) = 2.93, p = 0.09 analysis of variance showed no significance difference between the average improvement of two groups. Correlation between the degree of pain reduction showed significance only with BMI, or that higher BMI is associated with a lower degree of pain reduction. The results of this study showed that application of continuous ultrasound in patients with chronic pain, caused by degenerative changes in the musculoskeletal system, led to a significant reduction in pain. Different intensity and duration of ultrasound application showed no significant effect on the degree of pain reduction. Body mass index showed significant negative correlation with the degree of pain reduction, but age, gender and location of pain did not show significant correlation.