With a growing older population and an increasing prevalence of age-related health conditions, inappropriate prescription (IP) has become a concern in public health. Potentially Inappropriate Medication (PIM) lists were developed to address issues related to IP in the older population.Systematically compare the approaches adopted to develop PIM lists.We searched MEDLINE (06/02/22) and reference lists of eligible studies, and we included the most recent version of explicit PIM lists published from 1990 onwards in English or German. Two reviewers performed the screening, and one extracted the data. A second reviewer double-checked 20% of the data extraction. We identified key approaches and synthesised them narratively.We included 31 PIM lists, consisting of new lists (N = 18) or updates (N = 8), adjustments-validation (N = 3) and extensions of old lists (N = 2).Twenty studies focused on a specific geographic location and five on a particular condition. The others were general lists. The definition of the older population ranged from ≥65 to ≥75 years.The sources explored to determine eligible drugs varied significantly. PubMed was the most searched database, and most studies relied on previously published lists to create their own. Two studies underwent critical appraisal and certainty of evidence assessment.The Delphi was the widely used consensus technique. However, there were extensive variations in the organisation of the first draft, panellist selection, consensus thresholds and the presentation of the final list.Given the variability of the methods used, creating a consensus to standardise the development of PIM lists has become critical.