Pharmacogenomics is a growing area of pharmacy that has the potential to improve individualization of medication choices, dosing and predictability of side effects. Clozapine and risperidone are atypical antipsychotics whose metabolism, efficacy and side effects are influenced by single nucleotide polymorphisms (SNPs) in a patient's genetic makeup. It has been shown that a polymorphism in the D3 dopamine receptor is associated with an increased risk in developing tardive dyskinesia as an adverse event while taking risperidone. Also, there is evidence that a patient with a homogenous C genotype in the gene coding for the 5-HTzc receptor has a higher risk of weight gain from taking clozapine than a patient with a heterogeneous T genotype of that same gene. There are many other SNPs that have been, or are currently being, investigated with regards to the efficacy and side effects of clozapine and risperidone. However, more studies with longer durations and larger sample sizes are needed to determine the actual clinical significance of these genetic variants. In the future, pharmacists have the opportunity to become leaders in the area of pharmacogenomics to help apply this information to optimize patient outcomes and minimize adverse events.