Abstract-In this letter, we study the global asymptotic stability of FAST TCP in the presence of network feedback delays. Based on a continuous-time dynamic model of FAST TCP and a static approximation of queuing delay at the link, we derive stability conditions for FAST TCP. The derived conditions are explicitly appeared as tuning parameter conditions of FAST TCP, and hence can be satisfied in a distributed way. The simulation results illustrate the validity of the conditions for the global asymptotic stability.