Background Disagreement among healthcare professionals on the clinical relevance of drug-related problems can lead to suboptimal treatment and increased healthcare costs. Elderly patients with chronic non-cancer pain and comorbidity are at increased risk of drug related problems compared to other patient groups due to complex medication regimes and transition of care. Objective To investigate the agreement among healthcare professionals on their classification of clinical relevance of drug-related problems in elderly patients with chronic non-cancer pain and comorbidity. Setting Multidisciplinary Pain Centre, Rigshospitalet, Copenhagen, Denmark. Method A pharmacist performed medication review on elderly patients with chronic non-cancer pain and comorbidity, identified their drug-related problems and classified these problems in accordance with an existing categorization system. A five-member clinical panel rated the drug-related problems’ clinical relevance in accordance with a five-level rating scale, and their agreement was compared using Fleiss’ κ. Main outcome measure Healthcare professionals’ agreement on clinical relevance of drug related problems, using Fleiss’ κ. Results Thirty patients were included in the study. A total of 162 drug related problems were identified, out of which 54% were of lower clinical relevance (level 0–2) and 46% of higher clinical relevance (level 3–4). Only slight agreement (κ = 0.12) was found between the panellists’ classifications of clinical relevance using a five-level rating scale. Conclusion The clinical pharmacist identified drug related problems of lower and higher clinical relevance. Poor overall agreement on the severity of the drug related problems was found among the panelists.