A total 71 male athletes (weight lifters, wrestlers, orienteers, and ice-hockey players) and 21 non-athletes were randomly selected, for a baseline MRI study. After 15 years all the participants at baseline were invited to take part in a follow-up examination, including a questionnaire on back pain and a follow-up MRI examination. Thirty-two athletes and all non-athletes had disc height reduction at one or several disc levels. Disc degeneration was found in more than 90% of the athletes and deterioration had occurred in 88% of the athletes, with the highest frequency in weight lifters and ice-hockey players. 78% of the athletes and 38% of the non-athletes reported previous or present history of back pain at baseline and 71 and 75%, respectively at follow-up. There was no statistically significant correlation between back pain and MRI changes. In conclusion, athletes in sports with severe or moderate demands on the back run a high risk of developing disc degeneration and other abnormalities of the spine on MRI and they report high frequency of back pain. The study confirmed our hypothesis, i.e. that most of the spinal abnormalities in athletes seem to occur during the growth spurt, since the majority of the abnormalities demonstrated at follow-up MRI after the sports career were present already at baseline. The abnormalities found at young age deteriorated to a varying degree during the 15-year follow-up, probably due to a combination of continued high load sporting activities and normal ageing. Preventive measures should be considered to avoid the development of these injuries in young athletes.