Objective There is evidence to suggest that older adults are underrepresented in randomized controlled trials of health interventions. The aim of this review was to systematically examine the age-related inclusion criteria distribution of participants in randomized controlled trials (RCTs) of low back pain (LBP) interventions and to investigate if this distribution pattern changes over time. Methods We identified, in PubMed, 1,047 RCTs on nonspecific LBP published since 1992, of which a random sample of 400 was assessed for inclusion in the review. Included studies were grouped according to treatment type. Data were extracted on year of publication, types of treatment, total number of participants, age inclusion criteria, and age of included participants. Results A total of 274 RCTs published between 1992 and 2010 met the inclusion criteria. A total of 41.6% (n = 114) of the included trials excluded people ages >65 years. The pooled mean age of participants was 44.3 years (95% confidence interval 42.4-46.3); the pooled minimum age for inclusion was 19.8 years and the pooled maximum age for inclusion was 65.4 years. We found no trend of including older participants in RCTs on LBP over time. Conclusion Despite an aging population around the globe, older adults are largely excluded from RCTs evaluating management of LBP, and there is no evidence of change in this practice over the last 2 decades.