Artificial intelligence (AI) is transforming medical writing. We investigated the impact of AI among professional medical writers practising in Spain. Professional medical writers from the community of the Asociación Española de Redactores de Textos Médicos (AERTeM; Spanish Association of Medical Text Writers) were invited to participate in a web-based survey. Among 53 respondents, 47% had over ten years’ experience, and 92.5% used AI, mainly large language models, for editing, literature searches, and text refinement. Time saving was the main benefit, whereas the economic impact was minimal. Main concerns for AI users and non-users included confidentiality, bias, plagiarism, and limited suitability for scientific review. Widespread AI adoption underscores the need for structured training and strategic guidance to support its effective and responsible use.