Abstract Introduction: The use of complementary and alternative medicine (CAM) in cancer patients has been documented in major cities across USA, Canada, Europe, Nigeria, and Saudi Arabia. These studies suggest that cancer patients on chemotherapy simultaneously use CAMs. In Ireland, there have been two studies in pediatric cancer centers that have documented the use of CAM. To our knowledge, no study has examined the use of CAM in the adult population in Ireland. Method: A cross-sectional survey was conducted at a single adult cancer center over a three-week period. The survey was offered to all oncology and hematology patients attending the medical day unit. Results: The survey was completed by 81 patients, 51 of them were females (63%). The majority (93.8%) of the patients in our sample were in the age range of 41-80. 47 (58%) of the patients reported using CAM concurrently with conventional chemotherapy. The average cost of CAM was under €20 per month, but five patients (6.2%) spent over €100 per month. The major reasons for taking CAM were to enhance quality of life (23.5%), improve psychological/emotional wellbeing (17.3%), improve immunity (16%), relieve side effects of cancer (9.9%), relieve side effects of treatment (8.6%), and to directly treat/cure cancer (2.5%). Patients using CAM reported their source of information as healthcare professionals (30.9%), family/friends (19.8%), media (13.6%), and CAM practitioners (2.5%). Out of 81 patients, only 27 (33.3%) discussed the use of CAM with a healthcare professional involved in their care, of which 18.2% asked regarding interactions with the conventional therapy, 18.2% asked regarding CAM effectiveness and the type to use, 16.7% asked advice whether to pursue it, and 15.2% asked regarding safety of CAM. From the 26 patients using CAM who did not discuss with HCP the reasons cited were that they were never asked by the HCP (25.9%), did not think it was important to discuss with the HCP (13.0%), and 61.1% did not specify their reason. Of the 81 patients, 18 consumed herbal products (13.6% green tea, 8.6% flax seed, 3.7% evening primrose, 2.5% soy supplements), 34 used dietary supplements (28.4% vitamins, 12.3% minerals, 3.7% fish oils), and 21 used other CAMs (8.6% massage, 7.4% meditation/mind-body technique, 7.4% acupuncture, 6.2% reflexology, 2.5% reiki). Conclusion: The use of CAM in adult cancer patients has not been well documented in Ireland. As demonstrated from the pilot study, adult cancer patients in Ireland do seek out CAMs when simultaneously receiving chemotherapy, highlighting the importance for physicians to explicitly ask all patients regarding their intentions of CAM in order to provide safe and evidence-based options. This cancer center appeared to not have patients pursuing ayurvedic or Chinese medicine. However, similar conclusions cannot be made for other urban centers with more diverse population mixes with differing cultural experiences and attitudes to CAM. Citation Format: Karmali S, Markey G, Killian M, Ahmed G, Bird BR, Murphy CG. Use of complementary and alternative medicine in cancer patients receiving chemotherapy in Ireland [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-14-05.