Background: Chemotherapy induced nausea and vomiting (CINV) is prevalent and potentially treatment-limiting side effects in cancer patients.1 Nausea and vomiting are frequent and significantly affect cancer patients' daily functioning and health-related quality of life (HRQL). A patient who experienced nausea and vomiting showed to be affected by worse physical, cognitive, social functioning, and global quality of life in comparison to patients who don’t have nausea and vomiting. Methods: We conducted a prospective cohort observational study to assess the complete response (CR) and risk factor associated with nausea and vomiting among HSCT patients at King Fahad Medical City (KFMC). All adult patient underwent Bone Morrow Transplant (BMT) were included in the study. Data was collected prospectively during admission to the hospital and receive the conditioning regimen. Patients was interviewed by clinical pharmacist and assessed using MASCC Antiemesis Tool© (MAT) to assess the effectiveness of our regimen used to prevent nausea and vomiting during active chemotherapy days and delayed phase. Results: A total of 30 patients were enrolled in the study during a one year follow up from April 2021 to April 2022. Data analysis was done and revealed as follows; out of 30 patients enrolled 18 (60%) patients were female while 12 (40%) were male. Lymphomas including (Non-Hodgkin, and Hodgkin lymphomas) were the most common diagnosis included among patients 17 (56.6%). BEAM protocol was the most common conditioning regimen protocol used 13 (43.3%). Complete response (CR) was achieved in 13 (43.3%) patients during acute nausea and vomiting, while 17 (56.7%) patients weren’t being able to achieve CR. Furthermore, out of the 30 patients observed, 6 (20.0%) experienced delayed vomiting, while 19 (63.3%) experienced delayed nausea. Similarly, Complete response (CR) was achieved in 11 (36.7%) patients during delayed nausea and vomiting, while 19 (63.3%) patients weren’t being able to achieve Complete response (CR) respectively. Breakthrough medication for nausea and vomiting was needed in all patients who didn’t have to achieve CR 19 (63.3%) patients. There was no association between age, gender, conditioning regimen, and type of transplant and achieved CR among patients (P- value; > 0.05). However, more breakthrough medication is needed when CR is not achieved (P- value; < 0.05). Conclusions: At our institution, among hematopoietic transplant recipients receiving appropriate antiemetics, approximately half (50%) achieved complete response (CR) in preventing chemotherapy-induced vomiting (CINV). Age, gender, and transplant type were not significantly associated with increased CR failure, while the specific conditioning regimen did not show a statistically significant impact.