Abstract. Zagier showed that the Galois traces of the values of j-invariant at CM points are
Fourier coecients of a weakly holomorphic modular form of weight 3=2 and Bruinier-Funke
expanded his result to the sums of the values of arbitrary modular functions at Heegner points.
In this paper, we identify the Galois traces of real-valued class invariants with modular traces of
the values of certain modular functions at Heegner points so that they are Fourier coefficients
of weight 3=2 weakly holomorphic modular forms.