This guideline provides recommendations for diagnostic and therapeutic procedures for patients with malignant gliomas. We differentiate evidence-based standards from reasonable options or non-evidence-based measures that should no longer be considered. The recommendations herein should provide a framework and assurance for the choice of diagnostic procedures and therapeutic measures and aim to reduce complications from unnecessary treatment and cost. The guideline contributes to a critical appreciation of concurrent drugs with a focus on the controlled use of anticonvulsants and steroids. It should serve as a guideline for all professionals involved in the diagnostics and care of glioma patients and also as a source of knowledge for insurance companies and other institutions involved in the cost regulation of cancer care in Europe. Implementation of the recommendations summarised here will need interdisciplinary structures of care for patients with brain tumours and structured processes of diagnostic and therapeutic procedures.