PURPOSE: We wanted to evaluate the relationship among the myelography, magnetic resonance imaging (MRI), and electromyography (EMG) findings in young patients with low back pain, and we wanted to assess the significance of the spinal geometric measurements as well as type of disc herniation seen on MRI. MATERIALS AND METHODS: Forty-four young men with lower back pain were included, and they were all clinically suspected of suffering with lumbar disc herniation. All of them underwent myelography, MRI and EMG. We measured spinal geometry including the anteroposterior diameters of the central canal and thecal sac, the interlaminar distance, the width of the lateral recess and the thickness of the ligamentum flavum, and we evaluated for root deviation as well as disc herniation on the MRIs. We compared the types of disc herniation on MRI with the myelography and EMG findings. Also, we investigated the correlation of the spinal geometric measurements on MRI with the EMG and myelography findings. RESULTS: The types of disc herniation on MRI were not significantly related to the myelography (p = 0.298) and EMG findings (p = 0.372). The EMG findings were not related to either the myelography findings (p = 0.435) or the spinal geometric measurements (p > 0.05) on MRI. Nerve root compression that was noted on myelography was related to the thecal sac AP diameter (p = 0.016) and the width of the lateral recess (p = 0.011). There were no correlations between myelography and the findings of root deviation on MRI (p=0.052). CONCLUSION: MRI can play an excellent diagnostic role for young patients with radiculopathy or lower back pain. It could increase the diagnostic accuracy if it is used in conjunction with myelography and EMG. The narrowing of thecal sac AP diameter and the width of lateral recess rather than the type of disc herniation on MRI were well correlated with the myelography and EMG findings.