An arrangement for estimating IQ-imbalance of a received OFDM-signal is disclosed. The arrangement comprises an FFT-unit (410) adapted to transform the received OFDM-signal to a frequency domain. The frequency domain comprises a plurality of sub-carrier frequencies, and the transformed received OFDM-signal comprises pilot symbols on one or more sub-carrier frequencies and symbols other than pilot symbols on one or more other sub-carrier frequencies. The arrangement also comprises channel estimation circuitry (430, 445), and an IQ-imbalance estimation unit (440) adapted to estimate the IQ-imbalance based on at least one of the pilot symbols, a determined estimated channel value for the sub-carrier frequency of the at least one pilot symbol, an estimate of the transmitted information symbol on the corresponding mirror sub-carrier frequency associated with the at least one pilot symbol and an estimated channel value for the corresponding mirror sub-carrier frequency associated with the at least one pilot symbol. Wherein the corresponding mirror sub-carrier frequency comprises a symbol other than a pilot symbol. A corresponding method and a computer program product are also disclosed.