Despite the advance in supportive care that occurred with the introduction of selective serotonin subtype 3 (5-HT3) receptor antagonists, control of chemotherapy-induced nausea and vomiting (CINV) with first-generation agents (ondansetron, dolasetron, and granisetron) is less than ideal. Palonosetron is a unique 5-HT3 receptor antagonist whose distinctive pharmacologic characteristics (ie, high 5-HT3 receptor binding affinity, prolonged half-life) result in superior clinical benefit. Superiority of palonosetron over ondansetron and dolasetron in the prevention of both acute and delayed CINV has been observed in each phase III trial conducted. Of note, such evidence of superiority has never been seen in US Food and Drug Administration (FDA) registration trials of other approved agents in this class. Recently approved by the FDA, palonosetron 0.25 mg intravenously is indicated for the prevention of acute nausea and vomiting associated with initial and repeat courses of moderately and highly emetogenic cancer chemotherapy. Unlike other 5-HT3 receptor antagonists, palonosetron is also indicated for prevention of delayed nausea and vomiting associated with initial and repeat courses of moderately emetogenic cancer chemotherapy. Palonosetron exhibits an excellent tolerability profile, with frequency, severity, and duration of adverse reactions similar to that of comparator agents. Unlike older agents that are considered therapeutically interchangeable at equipotent doses, palonosetron should be considered a clinically distinct and superior treatment for the prevention of CINV.