The invention relates to a method and an apparatus for performing a microphone matching of a hearing aid comprising a first microphone, a second microphone and a receiver in a predetermined spatial arrangement to each other. The method comprises the steps of: generating an output sound signal by means of the receiver; picking up a first and second input sound signal by the first and second microphones while the output sound signal is generated; converting the first and second input sound signals into a first and second electrical microphone output signal by means of the microphones; determining a first and second microphone response of the microphones; determining a microphone response difference between the first microphone response and the second microphone response; determining a matching difference between the microphone response difference and a predetermined reference microphone response difference; and adapting at least a first microphone gain of the first microphone according to the matching difference to reduce the matching difference.