The invention relates to a method which monitors carrier frequency stability (ωi) of identical transmitter signals (si (t) ) in several transmitters Si of a common wave network. Said method is based on a calculation of carrier frequency displacement (ΔωI) of carrier frequency (ωi) in a transmitter (Si) in relation to carrier frequency (ω0) in a reference transmitter (S0). The phase displacement difference (ΔΔθi (tB2-tB1) ) caused by carrier frequency displacement (Δωi) between phase displacement (Δωi (tB1) ) is determined in order to form a moment of observation (tB1), and phase displacement (Δθi (tB2) ) is determined at a second moment of observation (tB2) of a received signal (ei (t)) in the transmitter (Si) associated with the respective transmitter signal (si (t) ) in order to form a received signal (e0(t)) of the reference transmitter (S0) associated with the reference transmitter signal (s0(t)).