This analysis compares the antiemetic efficacy of the 5-HT3-receptor antagonists granisetron and tropisetron in acute chemotherapy-induced nausea and vomiting (CINV). All published randomized studies comparing granisetron with tropisetron in conventionally-dosed, emetogenic chemotherapy are included in this pooled analysis. The target criterion for antiemetic success was 'acute complete response' (complete absence of vomiting in the 24 h after the start of chemotherapy) and the rate of successful treatment reported as 'response rate' (acute complete response rate per patient). Twelve studies were used comprising 810 patients. Comparison between granisetron and tropisetron in patients receiving cisplatin-based therapy showed superiority of granisetron (odds ratio above 1.0) in six out of seven studies. However, this difference did not reach statistical significance. In patients receiving noncisplatin-based therapies, four out of five studies showed an advantage of granisetron over tropisetron with one study showing a significant advantage. Pooled analysis of all studies demonstrated a significant overall advantage for granisetron over tropisetron (p=0.042). This is supported by the individual studies: overall, ten out of the 12 studies analyzed showed an advantage for granisetron, with a 6.4% difference in response rate. This advantage was more pronounced in noncisplatin-based therapy (7.3%), whereas in cisplatin-based therapy, the difference was 5.4%. The overall results of this pooled analysis of cisplatin and noncisplatin-based studies suggest that granisetron has a marginal but clinically potentially relevant statistically significant advantage in efficacy over tropisetron for the control of acute CINV.