Background: Endometriosis is a chronic inflammatory condition characterized by the presence of endometrial-like tissue outside of the uterine cavity. It affects approximately 6–12% among reproductive-age women. Laparoscopy is still the gold standard for diagnosing it. Since an average of couple of years elapses from the onset of symptoms to the definitive diagnosis, analysis of symptoms could serve as a non-invasive diagnostic tool. Methods: An anonymous survey was distributed online in November 2019. It contained 23 closed questions, which covered two areas: knowledge and awareness of endometriosis symptoms and its presence among respondents. Results: A total of 3319 women completed the survey, of which 328 were diagnosed with endometriosis (9.9%). The symptoms of endometriosis most often indicated by the general population were infertility and dysmenorrhea. In contrast, those least frequently indicated were painful defecation and dysuria. Respondents suffering from endometriosis indicated that they often or sometimes experienced dysmenorrhea (83%, n = 273), pelvic pain not related to menstruation (72%, n = 235), dyspareunia (68%, n = 223) and painful defecation or dysuria (40%, n = 132). Conclusions: Since the search for a non-invasive diagnostic endometriosis marker has been conducted for many years without success so far, it seems that awareness of the clinical presentation and reported symptoms may help to provide earlier diagnoses.