A method for the determination of a bias current of a quartz oscillator that includes the phases of: defining a series of bias currents of prefixed values; supplying to said quartz oscillator a bias current value not yet used; verifying the presence of an oscillation signal at the output of said quartz oscillator; supplying in the negative case to said quartz oscillator a bias current value not yet used and repeating the preceding phase; verifying the presence of the correct oscillation frequency; supplying in the negative case a bias current not yet used to said quartz oscillator and repeating the phase of verifying the presence of an oscillation signal at the output of said quartz oscillator; storing, in the positive case, that the supplied current is valid; repeating the preceding phases up to the exhaustion of said series of values of bias currents; fixing as a bias current of said quartz oscillator the algebraic average of the currents regarded as valid.