60 patients with acute low back pain will be recruited to a single-blinded, randomized, placebo-controlled trial. They are randomized to receive either shockwave therapy or sham treatment by a identically looking device for 4 weeks, twice a week. Additionally patients receive physiotherapy twice a week and are allowed to take an anti-inflammatory drug, if necessary for even 4 weeks. The primary outcome variable will be measured at day 0, every week during treatment (day 7; 14; 21 and 28) and up to 4 weeks after the last treatment. The clinical outcome will be primarily measured by pain intensity using a visual analogue scale. Secondary outcome measures are Oswestry Disability Index, Beck`s Pain Depression Scale, Roland Morris Disability Questionnaire and the EQ-5D. Data will be analysed for the difference in change of scores between groups using one-way t-test.