According to a recent Forrester study, adoption of IP telephony (IPT, also voice over IP or VoIP) systems by North American and European enterprises will continue to increase through 2005. We found that 36% of North American enterprises and 32% of European enterprises expect to increase IPT purchases in 2005. But with only 20% of North American enterprises and 11% of European enterprises saying that they have fully deployed IPT, a substantial replacement market for legacy systems remains. Both North American and European enterprises cited reliability as the most important purchase criterion, and cost is the largest obstacle to a timely purchase. As IPT purchase plans continue to accelerate, it is important for organizations to adequately prepare by upgrading their networks and aligning their IT organizations to support a successful migration to IPT.