Purpose: This paper discusses ranking factors suitable for library materials and shows that ranking in general is a complex process and that ranking for library materials requires a variety of techniques. Design/methodology/approach: The relevant literature is reviewed to provide a systematic overview of suitable ranking factors. The discussion is based on an overview of ranking factors used in Web search engines. Findings: While there are a wide variety of ranking factors applicable to library materials, todays library systems use only some of them. When designing a ranking component for the library catalogue, an individual weighting of applicable factors is necessary. Research limitations/applications: While this article discusses different factors, no particular ranking formula is given. However, this article presents the argument that such a formula must always be individual to a certain use case. Practical implications: The factors presented can be considered when designing a ranking component for a librarys search system or when discussing such a project with an ILS vendor. Originality/value: This paper is original in that it is the first to systematically discuss ranking of library materials based on the main factors used by Web search engines.