Extensive spectroscopic studies of stars with and without planetary systems have concluded that planet host stars are more metal-rich than those without detectable planets. More subtle trends of different chemical elements begin to appear as the number of detected extrasolar planetary systems continues to grow. I review our current knowledge concerning the observed abundance trends of light and heavy elements in planet host stars and their possible implications. These studies may help us to understand the chemical evolution of our Galaxy at supersolar metallicities.