The "Structured HIstory of Medication use" (SHIM) questionnaire is a tool developed to obtain an accurate pre-admission overview of medications, involving a structured interview with patients, and has demonstrated its potential to prevent reconciliation errors. The objective of this study was to cross-culturally adapt the SHIM questionnaire to Spanish.Forward and blind-back translations followed by a synthesis and adaptation, with the participation of an expert panel, to guarantee the equivalence between the original questionnaire and the Spanish version. Subsequently, pilot testing of the Spanish version was carried out through cognitive interviews in a sample of polymedicated patients under follow-up by the Department of Internal Medicine.The Spanish version of the SHIM questionnaire (SHIM-e) was obtained. Scores for difficulty assigned by translators involved in forward and back translations were low. During the synthesis and adaptation phase, three discrepancies were resolved, and the expert panel decided to include some terms commonly used for clinical interviews in the Spanish version of the questionnaire. The pilot testing, which was performed in a sample of 10 polymedicated patients admitted to the Department of General and Digestive Surgery, showed 100% comprehensibility for all items, except for number 13, which was 90%.This work presents the first cross-cultural adaptation to Spanish of the SHIM questionnaire. The forward and blind-back translations presented low difficulty and the results of the pilot testing showed a high level of comprehensibility for the Spanish version of this tool.