Introduction: Walking as a simple, safe, low-cost and easy available therapeutic exercise needs to be investigated more in patients with chronic low back pain. Therefore, this study aimed to investigate the effects of 10%-incline treadmill walking on back muscle endurance, pain, and disability and fear of movement in patients with chronic low back pain. Materials and Methods: Participants were divided into two groups of control (standard physiotherapy and walking on level treadmill, n = 6) and experimental (standard physiotherapy and 10%-incline treadmill walking, n = 5). Patients treated three times every week for four weeks. Muscle endurance, fear of activity, pain and disability were measured by modified Sorensen test, fear avoidance belief questionnaire, visual analogue scale and Oswestry disability questionnaire, respectively, before and after the study and two month after the treatment. Results: Between-group differences in back muscle endurance after the treatment (P = 0.01) and at follow-up time (P = 0.04) were significant. In intervention group, the changes in back muscle endurance (P = 0.53), pain (P = 0.26), disability (P = 0.50) and fear avoidance belief (P = 0.89) variables were not significant. In control group, the changes in back muscle endurance (P = 0.19), pain (P = 0.57), disability (P = 0.22), and fear avoidance belief (P = 0.23) variables were not significant. Between-group changes in pain (0.14), disability (P = 0.71) and fear avoidance belief (P = 0.27) variables were not significant. Conclusion: There is significant difference in the level of increased back muscle endurance between the 10% and base inclination groups. It seems that base inclination is more effective.