In this article I review surface abundances in stars which host planetary systems. Recent spectroscopic studies of stars with and without planetary systems have concluded that stars which host planets are more metal-rich than those without planets. We discover more subtle trends of different chemical elements as the number of detected exoplanets continues to grow. However, in most cases the abundance trends of planet-host stars are very similar to those of the comparison sample. Possible explanations for the abundance anomalies or the correlation between [Fe/H] and the presence of giant planets have certain implications for planetary formation and evolution theory, Galactic chemical evolution and astrobiology. These studies are very useful for verifying galactic models at high metallicities and consequently improve our knowledge of stellar nucleosynthesis and galactic chemical evolution.