PURPOSE: Over the past years, there has been a considerable increase in complementary and alternative medicine (CAM) use among cancer patients. However, guidance from health care workers (HCWs) is not always provided. We aimed to determine the knowledge, attitude and practice of Tunisian HCWs regarding the use of CAM in cancer patients. METHODS: We conducted a multicenter cross-sectional study over 5 months from February to June 2022 among HCWs caring for cancer patients in the Tunisian center region. Data were collected using a self-administered questionnaire developed by our investigators. RESULTS: The level of knowledge about CAM was declared limited by 78.4% of our population. The best known CAM therapies were herbal medicine and homeopathy while chiropractic and hypnosis where the least. HCWs who had sought information on CAM represented 54.3% of our sample and the main source of information was the Internet (37.1%). A positive attitude towards the use of CAM was found in 56% of HCWs. The integration of CAM into supportive care in oncology was approved by 78% of HCWs. Concerning training on CAM, 78% declared its necessity for HCWs and 73.3% expressed a desire to have it. A personal use of CAM was found in 53% of HCWs while 38.8% had previously used CAM in the treatment of their cancer patients. CONCLUSION: The majority of HCWs had a positive attitude towards the use of CAM in oncology despite their poor knowledge about it. Our study emphasizes the need to train HCWs dealing with cancer patients on CAM.