Spondylolysis and spondylolisthesis are common etiologies of low back pain, the prevalence of these diagnoses is around 6~7%. Up to 90% of spondylolysis occur at L5 lumbar vertebrae, sponsylolisthesis most commonly occurs at L5-S1 level. Around 20-40% of spondylosis may progress to spondylolisthesis. Some patients diagnosed with spondylolysis or spondylolisthesis by image may be without symptoms. Low back pain is not rare among military pilots. For those pilots, spondylolysis or spondylolisthesis hardly lead to sudden incapacitation. However, pain from these condition may be distracting, nerve root compression may affect G-tolerance and flight safety. The flight surgeon should be aware of the potential risks of spondylolysis and spondylolisthesis. Waiver is based on the safety of aviation; symptoms, differential diagnosis, comprehensive examination, treatment response should all be put into consideration.