Low back pain is a common condition. This is a retrospective study of new referrals to neurosurgical outpatients at the Western Hospital, Victoria, Australia. Two hundred and fifteen histories were systematically reviewed. Statistical analysis was performed using univariate and multivariate analyses. Patients who had tried physiotherapy, epidural injection or had no pre-outpatient imaging were more likely to get MRI (p<0.02). Patients with clinical features of neurogenic claudication (p<0.01) or with neurological signs (p=0.02) were more likely to proceed to surgery. CT scan demonstrated significant correlation to MRI for lumbar canal stenosis, disc disease or the absence of disease (p<0.01). Referral guidelines for general practitioners regarding back pain are proposed. Recommendations are also made to facilitate the selected use of CT scan and MRI.