Background and Purpose: People who live longer often live with multimorbidity. Nevertheless, whether the presence of multimorbidity affects pain and disability in older adults with chronic low back pain (LBP) remains unclear. The aim of this study was to investigate whether multimorbidity predicts pain intensity and disability at 6- and 12-month follow-ups in older adults with chronic LBP. Methods: This was a prospective, longitudinal study with 6- and 12-month follow-ups. Participants with chronic LBP (age ≥ 60 years) were recruited and interviewed at baseline, 6 months, and 12 months. Self-reported measures included the number of comorbidities, assessed through the Self-Administered Comorbidity Questionnaire, pain intensity, assessed with the 11-point Numerical Rating Scale, and disability, assessed with the Roland-Morris Disability Questionnaire. Data were analyzed using univariate and multivariate regression models. Results and Discussion: A total of 220 participants were included. The number of comorbidities predicted pain intensity at 6-month (β= 0.31 [95% CI: 0.12 to 0.50]) and 12-month (β= 0.29 [95% CI: 0.08 to 0.50]) follow-ups. The number of comorbidities predicted disability at 6-month (β= 0.55 [95% CI: 0.20 to 0.90]) and 12-month (β= 0.40 [95% CI: 0.03 to 0.77]) follow-ups. Conclusion: The number of comorbidities at baseline predicted pain and disability at 6-month and 12-month follow-ups in older adults with chronic LBP. These results highlight the role of comorbidities as a predictive factor of pain and disability in patients with chronic LBP, emphasizing the need for timely and continuous interventions in older adults with multimorbidity to mitigate LBP-related pain and disability.