Introduction: Many athletes seek consultation from sports medicine or spine care providers for low back pain. Low back pain accounts for 5-8% of all sports injuries, next only to knee, ankle and shoulder. Only three reports of lumbar facet fractures in athletes can be found in the literature but none have been reported in runners. The awareness about the condition is important in identifying and treating the cause of low back pain. Case presentation: A twenty two year old female athlete studying in sports school and competing in 100 metres, 200m, 400m track events came to us with a history of low back ache for 7 years for which she had sought medical attention from various hospitals, preventing her from her athletic training and limiting her activities of daily living. She had previously been treated with physical therapy and one injection of steroid to her sacro-iliac joint which did not give her a lasting relief. On examination, she had tenderness over the fifth lumbar vertebra and extension of the spine was painful. She also had a Lenke 1 less than 30 degree scoliosis which did not need any active intervention. Radiographs showed facet tropism at L5-S1 facet joint. CT scan showed undisplaced fracture line involving the inferior articulating process of L5, sclerosis of the proximal fragment, de-mineralisation of the distal fragment with significant right sided facet joint arthropathy at L5/S1 level. MRI scan showed right L5-S1 facet joint hypertrophy. There was no features of sacro ilitis. Right side facet joint block was given which produced relief of her symptoms, confirming the pain to be of the facet origin. She underwent right trans-foraminal lumbar interbody fusion at L5-S1 level. She has complete relief of her symptoms at 12 month follow up and has no problems with her day to day activities, although she has stopped her sports activities due to fear of recurrence of pain Conclusion: Lumbar facet stress fracture is a very rare condition and awareness about the condition is important to identify and treat the condition. It may require surgical fusion if not completely responding to conservative measures.