To evaluate the MRI findings in the lumbar spines of asymptomatic elite junior tennis players. The lumbar spine MRI studies of 98 asymptomatic junior elite tennis players (51 male, 47 female) with a mean age of 18 years (age range 11.2-26.3 years; standard deviation 3.1) was reviewed by two consultant musculoskeletal radiologists using consensus opinion. Images were assessed using accepted classification systems. Four players (4 %) had no abnormality. Facet joint arthropathy occurred in 89.7 % of the players, being mild in 84.5 % of cases. There were 41 synovial cysts in 22.4 % of the cohort all occurring in the presence of facet arthropathy. Disc degeneration was noted in 62.2 % of players, being mild in 76.2 % of those affected. Disc herniation was noted in 30.6 % of players, with 86.1 % of these being broad based and 13.9 % being focal. There was nerve root compression in 2 %. There were 41 pars interarticularis abnormalities in 29.6 % of patients, 63.4 % of these being grades 1-3. There was grade 1 spondylolisthesis in 5.1 % of players. The prevalence of facet joint arthropathy, disc degeneration, disc herniation and pars interarticularis fracture was lower in female players than in male and lower in the under 16-year-olds compared with the over 20-year-olds. There is a significant amount of underlying pathology that would normally go undetected in this group of asymptomatic elite athletes. Whilst these findings cannot be detected clinically, their relevance is in facilitating appropriate prehabilitation to prevent loss of playing time and potentially career-ending injuries.