Preventing and managing chemotherapy-induced nausea and vomiting (CINV) remain important goals. The objective of the Pan Australasian chemotherapy-induced emesis burden of illness (PrACTICE) study was to describe the incidence of CINV after highly or moderately emetogenic chemotherapy (HEC or MEC) for cancer in current clinical practice in Australia and five Asian countries (China, India, Singapore, South Korea, and Taiwan). This prospective, observational study of CINV was conducted at 31 sites in these six countries from August 2011 through September 2012 and enrolled male and female adult patients (a parts per thousand yen18 years of age) na < ve to HEC and MEC who were scheduled to receive at least two cycles of single-day chemotherapy. The primary effectiveness endpoint was complete response, defined as no vomiting or use of rescue therapy, during chemotherapy cycle 1 in the overall phase (0-120 h), acute phase (0-24 h), and delayed phase (> 24-120 h). Study outcomes were analyzed descriptively. Primary outcomes, CINV incidence, and treatment patterns (chemotherapy, CINV prophylaxis, rescue medication prescription, and rescue medication use) were assessed by phase (overall, acute, delayed), by cycle (as appropriate), within and across countries, and by level of chemotherapy emetogenicity (HEC vs MEC). The impact of CINV in cycle 1 on CINV in cycle 2 was analyzed for all patients with evaluable data for cycle 2. No site-specific analyses were performed. The remainder of this special series of papers reports on the results of this study.