  We analyze the renormalization group equations for the Standard Model at the
one and two loops levels. At one loop level we find an exact constant of
evolution built from the product of the quark masses and the gauge couplings
$g_{1}$ and $ g_{3}$ of the $U(1)$ and $SU(3)$ groups. For leptons at one loop
level we find that the ratio of the charged lepton mass and the power of
$g_{1}$ varies $\simeq 4\times 10^{-5}$ in the whole energy range. At the two
loop level we have found two relations between the quark masses and the gauge
couplings that vary $\simeq 4\%$ and $\simeq 1\%$, respectively. For leptons at
the two loop level we have derived a relation between the charged lepton mass
and the gauge couplings $g_ {1}$ and $g_{2}$ that varies $\simeq 0.1\%$. This
analysis significantly simplifies the picture of the renormalization group
evolution of the Standard Model and establishes new important relations between
its parameters.
