Rationale Viscosupplementation (VS) with hyaluronic acid is widely used in the management of knee osteoarthritis. There is no clear recommendation on the decision-making to achieve VS. Design Based on extensive research of the literature and expert opinion, the members of the EUROVISCO (European Viscosupplementation Consensus Group) task force were asked to give their degree of agreement with 60 issues, using a Delphi method. Results The expert panel achieved unanimous agreement in favor of the following statements: It is recommended to assess pain on a visual or 10-point numeric scale before considering VS. VS can be considered for patients with pain scores between 3 and 8. A standard x-ray must be obtained before the decision of VS. If the x-ray is normal, osteoarthritis must be confirmed by MRI or computed tomography (CT) arthrogram before considering VS. The aims of VS are relieving pain, improving function, and reducing non-steroidal anti-inflammatory drug (NSAID) consumption. The use of VS must not be considered for treating an osteoarthritis flare. VS can be envisaged as a first-line pharmacological treatment in patients having a contra-indication to NSAIDs or analgesics. VS can be considered in patients with contra-indications to arthroplasty. In the case of severe comorbidities (diabetes, hypertension, gastrointestinal disorders, renal failure), VS can avoid the use of potentially dangerous treatments. VS can be considered in patients receiving antiplatelet agents, vitamin K antagonists, and direct factor Xa or thrombin inhibitors. Five other statements obtained a high level of consensus. Conclusion These recommendations, illustrated in a decision algorithm, have been established to help practitioners in the decision-making of knee VS.