A double-blind study of the efficacy of spinal adjustive therapy delivered by chiropractors was designed and implemented at the clinic of a chiropractic college. 19 patients with low back pain completed a nominal two-week period of treatment. Nine patients in the experimental group received a series of chiropractic ‘adjustments’, while ten control patients received a comparable series of manual interventions. Experimental patients had significantly more relief from pain (+1.3) than control patients (+0.7) immediately after being treated as measured on a 10 cm Visual Analogue Scale. After two weeks of treatments the experimental patients as a group exhibited significant overall pain relief (+2.3), whereas improvement of patients in the control group was not significant (+0.6). Using a global index for the objective measurements of change in spinal mobility, it was also concluded that experimental patients improved significantly (global index change=2.08). Because of the small sample size, the results reported must be considered preliminary. Modification in the research design from other trials studying manipulative therapy included use of chiropractic adjustments as the form of manipulation, use of a realistic manual control treatment and use of a global index as an outcome measure.