Spondylodiscitis is a rare complication after facet joint steroid injection. This article presents a 78-y-old male with chronic back pain and facet joint arthritis who developed Pseudomonas aeruginosa L2-L3 and L3-L4 spondylodiscitis after computed tomography-guided facet joint steroid injection. Magnetic resonance imaging, fine needle aspiration and cultures confirmed the diagnosis. The patient was treated with intravenous administration of amikacin, and imipenem plus cilastatin for 4 weeks, followed by oral administration of ciprofloxacin for another 10 weeks. Sterile preparation prior to facet joint steroid injection should be stressed. To the best of our knowledge, this is the only reported case of iatrogenic spondylodiscitis after facet joint steroid injection. This iatrogenic complication should be considered in the risk-benefit analysis of facet joint diagnostic or therapeutic injections.