Many factors are associated with low back pain (LBP), including provocative spinal postures. Consequently, lumbo-pelvic posture is commonly assessed in LBP patients. A novel wireless monitor (BodyGuard (TM)) can monitor lumbo-pelvic sagittal plane movements reliably, and has demonstrated concurrent validity during non-functional tasks.This study evaluated the concurrent validity of this monitor during functional tasks, as a precursor to LBP field studies. Twelve painfree participants performed a series of postural tasks (in sitting and standing) three times. Simultaneous postural measurements were obtained by the wireless monitor and a laboratory-based system (CODA (TM)).Postural measurements were strongly correlated (r(s) - 0.88, r(2) - 0.78). The mean difference observed was small (<10% lumbo-pelvic ROM), however some tasks displayed greater error.The results support the concurrent validity of the wireless monitor for analysing lumbo-pelvic posture during functional tasks. Specific limitations of the monitor for certain postural tasks were identified, and should be considered before implementation in future field studies. (C) 2011 Elsevier Ltd. All rights reserved.