Current evidence for the usefulness of prophylactic antiemetic drugs in opioid-induced nausea and vomiting (OINV) in cancer patients receiving opioid analgesics is limited. Further, antiemetic prophylaxis is not considered necessary in the Guideline for Cancer Pain Management by the Japanese Society of Palliative Medicine. However, prevention of side effects such as OINV is important when opioid analgesics are administered for adequate pain management and to maintain adherence. Cancer patients expect us to study factors affecting OINV and effective prophylactic measures for the condition. We retrospectively analyzed electronic records in our hospital. We found that female sex and the use of prophylactic antiemetics, chemotherapeutic agents, and steroids were statistically significant factors associated with opioid-induced nausea, and that female sex and radiation therapy were significant factors associated with opioid-induced vomiting. Especially in females, the frequency of nausea was significantly reduced in the group that received chemotherapy with antiemetics on the same day of receiving opioid analgesics, compared to the groups that did not receive chemotherapy, or that did not receive antiemetics but received chemotherapy. These results suggest that, especially in females, administering chemotherapy along with antiemetics on the same day may be one possible prophylactic measure for OINV.