The web ontology language OWL is still a very young language. Experience with the language will build an increasing pool of ontology design patterns and best practises. In this paper we introduce macros for OWL ontologies. Macros are able to formally specify and capture design patterns for the knowledge engineering task with OWL ontologies. Thus the user is enabled to conveniently reuse them. Macros lead to an enhanced maintainability of the ontology, to a higher level of abstraction in the specification (and thus closer to the human conceptualization), to a faster and less error-prone creation of the ontology (and thus to lower costs) and to automation of several tedious tasks in the ontology life cycle. We present example macros, discuss further applications, advantages and problems of macros, and discuss the development of an implementation to enable the usage of macros.