BACKGROUND: One of the main problems faced by physiotherapists in primary care is low back pain with or without radiation to lower limbs. There are many different treatment approaches for the management of low back pain. Despite the large amount of published studies, the evidence remains contradictory. OBJECTIVE: To evaluate the influence of the osteopathic manipulation of the sacroiliac joint on low back pain with or without radiation to lower limbs. METHOD: Single-blind randomized clinical controlled trial. Participants with low back pain with or without lower limb radiation were randomized to osteopathic manipulation of the sacroiliac joint group (intervention, 6 sessions) or to an electrotherapy group (control, 15 sessions) for 3 weeks. Measures were taken at baseline (week 0) and post-intervention (week 4). The primary outcome measures were pain (Visual Analogue Scale), functional disability (Oswestry disability index and Roland Morris questionnaire). The secondary outcome measure was pain threshold at muscular tender points in the quadratus lumborum, pyramidal, mayor gluteus, and hamstrings. RESULTS: In all, 37 participants completed the study. The results of the intragroup comparisons showed statistically significant improvements in both groups in the visual analogue scale (Osteopathic manipulation group, P= 0.000; Electrotherapy group, P= 0.005) and Oswestry disability index (Osteopathic manipulation group, P= 0.000; Electrotherapy group- P= 0.026) but not in the Roland Morris questionnaire (P= 0.121), which only improved in the intervention group (P= 0.01). The osteopathic manipulation was much more effective than electrotherapy improving to pain and functional disability. CONCLUSION: Osteopathic manipulation of the sacroiliac joint improves pain and disability in patients with sacroiliac dysfunction after three weeks of treatment.