Purpose To consider the various challenges raised by Voice over Internet Protocol (VoIP). These include commercial, technological, marketing and regulatory issues. Design/methodology/approach First explores the technological issues, such as quality assurance and load control, then marketing issues by contrasting the various service providers and their approaches, and finally regulatory concerns by comparing European and US approaches to issues such as emergency services, numbering, law enforcement and security. Findings VoIP raises complex questions beyond whether or not consumers get cheaper telephone calls. IP technology is ushering in a world of peer-to-peer communications that provides opportunities (and dangers) for multiple business models and players. Originality/value Provides an overview of the issues raised by a potentially disruptive technology and contributes a perspective on the opportunities and threats for incumbents and new entrants to the market.