Lower back pain has a high prevalence among the Mexican working population, with extensive social and economic repercussions. Official figures show that lower back pain accounts for 10.0 to 15.0% of sick leave excuses. However, this fails to identify any relationship between lower back pain and job conditions, since such leave is only granted if it can be shown that the condition was not work-related. The present study shows that such a relationship does in fact exist. A retrospective study examined all cases (n = 210) in which workers were granted sick leave for lower back pain in an IMSS (Mexican Government Health Insurance) hospital in Mexico City during a seven-year period. The results show the association and interactions between debilitating lower back pain and several work-related variables: job position, time-on-the-job, and physical effort and weight-carrying associated with the position. Causes of lower back pain and the difficulty in obtaining accurate, precise back pain diagnosis are discussed. A number of clinical, epidemiological, and legal strategies for the study and prevention of back pain are suggested.