Common symptoms associated with post-traumatic stress disorder (PTSD) include re-experiencing and avoiding trauma-related situations, negative cognitions and mood, and arousal. Early clinical research studies have shown that medical cannabis may minimize these debilitating symptoms. The present study analyzed patient-reported outcomes in patients using medical cannabis for PTSD in Canada. A voluntary online survey was completed by PTSD patients using medical cannabis at baseline, 4-months, and 10-months after initiating use of cannabis from a single medical cannabis provider. Patients reported on outcomes including present symptoms and medical conditions, quality of life (QOL), and side effects experienced from cannabis use. A total of 588 patients with PTSD, predominantly Caucasian (84.4%) males (77.7%) with an average age of 43 years, completed the survey at baseline. There were 58.3% and 48.3% of PTSD patients that reported also having depression and anxiety disorders, respectively. Seventy-eight of 139 (56.1%) patients reported experiencing severe pain at baseline, compared to only 15 (10.8%) patients after 4-months (p < 0.0001). Significant improvements were also seen in patients’ ability to cope with pain after 4 and 10 months of cannabis use (n = 100, p < 0.0001). Patients reported significant improvements in overall QOL (n = 39, p = 0.03) and general mood (n = 37, p = 0.0005), as well as experience with sleep (n = 31, p = 0.002) and concentration (n = 30, p = 0.006) after 4 and 10 months. Patients suffering from PTSD reported significant improvements in a variety symptoms and QOL indicators after 4 months of cannabis use. Cannabis use in this population should be further studied and considered as an alternative treatment option.