Although several studies have evaluated the frequency and consequences of medication errors, few have explored their causes. In particular, nurses' knowledge regarding medications has been evaluated minimally. This survey was conducted to determine how nurses master medications prescribed to their patients to determine problems nurses may have with prescribed drugs and identify possible support tools. A questionnaire was created and presented to nurses in a French cancer center. A majority of the respondents correctly identified pharmaceutical classes and medications, as well as administration and storage conditions. However, side effects, contraindications, and drug-drug interactions were not adequately identified. Nurses reported facing problems mainly related to drug administration, drug storage, and generic drugs and their therapeutic equivalence. Multiple tools are in development to help nurses in these areas. This collaborative study between pharmacy and care wards identifies some difficulties nurses have regarding drugs and will help to establish improvement measures within the hospital.