Two-hundred-and-six patients newly diagnosed to have endometriosis at laparoscopy were evaluated in order to see if endometriosis-associated symptoms are proportional to the extent of the disease, as assessed using the Revised American Fertility Society Classification, and if the extent worsens with age. At hospital admission 81% of the patients complained of dysmenorrhea, 54% of chronic pelvic pain and 27% of dyspareunia. At laparoscopy, 39% of the patients had stage I endometriosis, 13% stage II, 35% stage III and 13% stage IV. At statistical analysis, no significant differences were found in total endometriosis scores, in active scores or in adhesion scores in different age groups. Although a difference in prevalence rate for dysmenorrhea and dyspareunia stage I versus III was found, a trend of increasing severity of symptoms with more widespread disease was not evident. There was not a significant difference in prevalence rate of symptoms for different aspects of endometriosis (implants, cysts or adhesions). Our data show that the American Fertility Society classification does not reflect the intensity of endometriosis-associated symptoms, probably underestimating the most active forms of this disease, and does not allow to follow a possible natural progression of the disease.