The aim of this trial is to investigate and compare the effects of electrical stimulation (ES) program and ultrasound (US) therapy on pain, disability, trunk muscle strength, walking performance, spinal mobility, quality of life (QOL), and depression in the patients with chronic low back pain (CLBP). A total of 59 patients with definite CLBP were enrolled in this study. These patients were randomized into three groups. Group 1 (n = 20) was given an ES program and exercises. Group 2 (n = 19) was given an US treatment and exercises. Group 3 (n = 20) was accepted as the control group and was given only exercises. All of the programs were performed 3 days a week, for 6 weeks. The patients were evaluated according to pain, disability, walking performance, endurance, mobility, QOL, depression. The trunk muscle strength was measured with a hand-held dynamometer. All of the groups showed stastically significant improvements in pain, disability, muscle strength, endurance, walking performance, mobility, sub-scores of SF 36, and depression when compared with their initial status. The intergroup comparison showed significant difference in physical function, energy and social function sub-groups of SF-36, VAS pain, extensor muscle strength, between three groups. This difference was statistically significant in the groups 1 and 2 compared to the control group. There was also no significant difference between the groups 1 and 2. We observed that US treatment and ES treatment were effective in improving pain, isometric extensor muscle strength, and QOL in patients with CLBP.