Background: Low back pain (LBP) and adolescent idiopathic scoliosis (AIS) are common pediatric diagnoses. The workup for these diagnoses can be highly variable and can use significant health care resources. There has been no analysis to date on the use of imaging for workup of AIS and/or LBP.Methods: The Humana Private Payer Database was queried for clinical and financial information for patients with AIS and/or LBP using International Classification of Diseases (ICD-9) for LBP and AIS. Current procedural terminology codes related to magnetic resonance imaging (MRI) and radiographs for the thoracolumbar spine were used to identify patients with LBP and/or AIS that used these diagnostic imaging modalities. Only patients ages 10 to 19 years were included in this analysis.Results: The total number of patients with AIS and LBP was 18 696 and 56 560, respectively. Thoracolumbar imaging was used within the workup for 71.76% and 45.53% of patients with AIS alone and LBP alone, respectively. MRI was used for 2.92% and 9.53% of patients with AIS alone and LBP alone, respectively. Radiographic imaging was used for 71.06% and 42.63% for AIS alone and LBP alone, respectively. There was minimal variation among regions in use of MRI for AIS. For patients with LBP, the diagnosis with the highest use of MRI was ''sciatica'' (29.07%). Patients with both LBP and AIS had statistically higher rates of imaging (91.04%), MRI (18.99%), and radiographs (89.71%). Among patients with an MRI, 20.87% never had a radiograph. Reimbursement per patient for radiographs was $164 and $239 for AIS and LBP, respectively. Reimbursement per patient for MRI was $1,263 and $1,882 for AIS and LBP, respectively.Conclusions: There is substantial use of both MRI and radiographs for adolescents with LBP and/or AIS. Clinicians should be aware of the impact these diagnostic tests have on the patient and the overall health care system.