The invention relates to a method of establishing a voice call between a calling party's terminal (5), which is connected to a telephone network (4), and a called party's terminal (6), which is also connected to the telephone network (4), through an Internet Protocol (IP) network (1). To make the method as simple as possible, it is proposed to use conventional IP servers (2; 3) of IP service providers for providing access to the IP network (1). The IP network (1) includes at least one Voice-over-IP (VoIP) server (11), which controls the functions of telephony over the IP network (1). The VoIP server (11) receives the request for an IP call from the calling party, activates the still inactive terminal (6) of the called party over the telephone network (4), determines the IP addresses of the terminals (5, 6), and communicates the IP addresses to the respective other terminal (5; 6). The terminals (5, 6) then establish a voice call between them through the IP network (1).