Background: The use of systemic chemotherapy has survival and palliation benefits in oncological patients. Mortality at 30 days after the administration of systemic chemotherapy is considered as a quality and safety indicator of oncological patient care. The international mortality threshold is 5%, which is the figure used to compare institutions. Aim: To assess mortality at 30 days after the administration of ambulatory systemic chemotherapy in a regional referral center in adult cancer patients. Material and Methods: Retrospective observational study of patients receiving ambulatory systemic chemotherapy in the oncology service of a regional public hospital during 2018. The 30-day mortality rate was calculated. Demographic characteristics, baseline disease and the treatment received were recorded. Results: During the study period, 690 patients received ambulatory systemic chemotherapy. Chemotherapy was palliative in 76% of patients and 53% received a first line treatment. Seventeen (2.5%) died within 30 days of treatment administration. Nine deaths (52.9%) were definitely related to treatment and sepsis was the most frequent cause. Conclusions: Our mortality rates are similar to international data. This type of audit reviews local outcomes and identifies factors contributing to mortality aiming to improve standards of care.