Method for selecting and adjusting in a customised manner a hearing aid, including a signal processing unit configured to process an electrical signal coming from one or more microphones and to play a resulting processed electrical signal in an ear canal of a patient through a miniature loudspeaker, wherein processing of the electrical signal is adjustable by means of settings of one or more operating parameters of the signal processing unit, wherein the method comprises the following steps: A. receiving indications on one or more needs of a patient; B. receiving indications from the patient concerning his/her perception of his/her own hearing with respect to one or more listening situations by assigning a respective value on a first value scale having a lower limit and an upper limit; C. performing a Pure Tone Audiometry audiometric test, also known as audiometric PTA test, on the patient, wherein the patient wears a headset and hearing is not assisted by any hearing aid; D. performing an Acceptable Noise Level audiometric test, also known as ANL test, on the patient; E. in the case where the resulting value of the audiometric PTA test is not larger than 80 dB, performing a Speech in Noise test, also known as SPIN test, on the patient; F. in the case where the resulting value of the audiometric PTA test is larger than 80 dB, or in the case where the resulting value of the audiometric PTA test is not larger than 80 dB and the resulting value of the SPIN test is larger than 6, performing a Speech in Quiet test, also known as SPIQ test, on the patient, wherein the patient wears a headset; G. displaying the resulting values of the audiometric tests performed in steps C, D, E and/or F on a same second value scale; H. on the basis of said one or more needs of the patient on which indications have been received in step A and on the basis of the resulting values of all the audiometric tests which have been performed in steps C and D and E and F, selecting one or more available hearing aids, J. for each one of said one or more available hearing aids selected in step H, on the basis of said one or more needs of the patient on which indications have been received in step A and on the basis of the resulting values of all the audiometric tests which have been performed in steps C and D and E and F, automatically determining a related adjustment of operating parameters of the respective signal processing unit to allow meeting the needs determined in step A. A. receiving indications on one or more needs of a patient; B. receiving indications from the patient concerning his/her perception of his/her own hearing with respect to one or more listening situations by assigning a respective value on a first value scale having a lower limit and an upper limit; C. performing a Pure Tone Audiometry audiometric test, also known as audiometric PTA test, on the patient, wherein the patient wears a headset and hearing is not assisted by any hearing aid; D. performing an Acceptable Noise Level audiometric test, also known as ANL test, on the patient; E. in the case where the resulting value of the audiometric PTA test is not larger than 80 dB, performing a Speech in Noise test, also known as SPIN test, on the patient; F. in the case where the resulting value of the audiometric PTA test is larger than 80 dB, or in the case where the resulting value of the audiometric PTA test is not larger than 80 dB and the resulting value of the SPIN test is larger than 6, performing a Speech in Quiet test, also known as SPIQ test, on the patient, wherein the patient wears a headset; G. displaying the resulting values of the audiometric tests performed in steps C, D, E and/or F on a same second value scale; H. on the basis of said one or more needs of the patient on which indications have been received in step A and on the basis of the resulting values of all the audiometric tests which have been performed in steps C and D and E and F, selecting one or more available hearing aids, J. for each one of said one or more available hearing aids selected in step H, on the basis of said one or more needs of the patient on which indications have been received in step A and on the basis of the resulting values of all the audiometric tests which have been performed in steps C and D and E and F, automatically determining a related adjustment of operating parameters of the respective signal processing unit to allow meeting the needs determined in step A.