Background: Despite lack of clinical trials reporting on beneficial effects of the cannabis plant for cancer-associated symptoms, its use is increasing worldwide. Approximately 10,000 Israeli cancer patients receive permits for the use of medical cannabis, making cannabis one of the most commonly prescribed oncology treatments in Israel and making the Israeli oncologists highly experienced with its use. The experience gained by the Israeli oncologists is therefore highly valuable. Methods: We conducted a web-based survey among all 238 Israeli oncologists, addressing personal experience; knowledge and attitudes toward the use of cannabis in oncology. Results: Response rate was 54% (n = 126), with the vast majority (87%) regularly prescribing cannabis to their patients. Anorexia, pain and nausea were the most common indications for cannabis use. While 90% of responders stated lack of sufficient knowledge regarding cannabis, its use was perceived as effective and safe. Interestingly, while most oncologists stated that opioids should be used as a first line treatment for cancer pain, most would prefer cannabis for pain relief if needed by a close relative. Oncologists who support cannabis legalization were more likely to prescribe it. Conclusions: Our findings indicate extensive use and perception of medical cannabis despite lack of knowledge, and support about efficacy and indicate a unique role for moral attitudes affecting clinical decisions. These data call for the implementation of an educational program and practical guidelines enabling more consistent and rational approach toward cannabis role in oncology.