OBJECTIVES: Evaluating the outcomes of prophylactic care and estimating direct medical costs of CINV among patients receiving emetogenic chemotherapy in Germany. METHODS: Prospective, multi-center, cross-sectional, cost-of-illness study (3 hospitals and 3 office-based facilities). Two hundred eight patients receiving level 4 or 5 emetogenic chemotherapy (Hesketh classification) were evaluable. Data were obtained from chart reviews and patients' diaries. We provide data on the subgroup of 137 patients who received chemotherapy at hospital (mean age: 55 years; 61% male) and present costs from providers' perspective (hospital). RESULTS: Seventy-three patients (53%) reported at least 1 episode of nausea or vomiting, despite antiemetic prophylaxis. More patients experienced delayed than acute CINV (50% vs. 20%) and more patients reported nausea than vomiting (51% vs. 21%). Ninety percent and 71% of patients received prophylactic antiemetic regimens for acute or delayed CINV in compliance with ASCO (American Society of Clinical Oncology) guidelines, respectively. Twelve percent of patients receiving prophylaxis for delayed symptoms according to ASCO guidelines experienced delayed vomiting in contrast to 34% of the group whose treatment did not follow the guidelines (p <0.05). One patient was rehospitalized due to CINV; 12 patients received rescue medication at hospital. Mean direct medical costs for antiemetic prophylaxis per patient and treatment cycle were €34 (SD 11). Mean direct costs due to CINV per patient and cycle were €15 (SD 81). Staff time and material consumption associated with managing episodes of CINV was the main cost driver (92%). Rescue medication (administered inside hospital) is responsible for 8% of those costs. CONCLUSIONS: In the hospital setting we found considerable room for improvement in processes and outcomes of care regarding guideline adherence for antiemetic prophylaxis of delayed CINV. Aside from its clinical consequences, CINV has an additional economic impact in oncology centers. Improved CINV prophylaxis may potentially offset some of costs of CINV treatment.