ABSTRACT: Aim: The objective of this study was to investigate the effectiveness of a mindful walking program (MWP) in patients with chronic low back pain (CLBP). Methods: The trial was a two-armed, randomized, controlled single-center open clinical trial. The study was performed in the Outpatient Clinic for Integrative Medicine of the Charité-Universitätsmedizin Berlin. The participants were adults aged 18-65 years with CLBP (≥3 months) and an average low back pain within the past 7 days measured on a visual analog scale (VAS, 0 = no pain, 100 = worst imaginable pain) of at least 40 mm. The patients received either eight weekly MWP sessions or no intervention (control). The primary outcome was the perceived pain intensity assessed with a VAS (0-100 mm) after 8 weeks. The secondary outcomes included back function assessed by the Hannover Functional Questionnaire Backache (FFbH-R) and perceived stress assessed by the 14-item Cohen's Perceived Stress Scale (PSS-14). The results were obtained by analysis of covariance adjusted for the respective baseline values. Results: In total, 55 patients were randomized (MWP: n = 29, 82.8% female, mean (±standard deviation) age: 52.5 ± 8.6 years, pain: 56.4 ± 14.1 mm; control: n = 26, 84.6% female, 54.8 ± 7.5 years, pain: 55.4 ± 13.1 mm). After 8 weeks, compared with the control conditions, the MWP was not associated with a statistically significant benefit for pain (VAS), adjusted mean - 9.6 [-22.3 to 3.1], p = 0.136, clinical benefits for back function (FFbH-R), adjusted mean 2.2 [-4.2 to 8.6], p = 0.493, or stress (PSS-14), adjusted mean - 1.6 [-4.8 to 1.6], p = 0.326. Conclusion: In conclusion, compared with no intervention, mindful walking did not significantly improve pain, back function, or perceived stress in patients with CLBP. Clinical Trial registration: ClinicalTrials.gov (NCT01893073).