  We present the results for three-loop beta-functions for Yukawa couplings of
heavy Standard Model fermions calculated within the unbroken phase of the
model. The calculation is carried out with the help of the MINCER program in a
general linear gauge, and the final result is independent of the gauge-fixing
parameters. In order to calculate three-point functions, we made use of
infrared rearrangement (IRR) trick. Due to the chiral structure of the SM a
careful treatment of loops with fermions is required to perform the
calculation. It turns out that gauge anomaly cancellation in the SM allows us
to obtain the result by means of the semi-naive treatment of gamma5.
