What are the symptoms of erectile dysfunction? Symptoms of ED include. being able to get an erection sometimes, but not every time you want to have sex. Erectile dysfunction, or ED, is when it is hard to get or keep an erection that's firm enough for sex. ED affects as many as 30 million men. Dec 7, A man is considered to have erectile dysfunction if he regularly finds it difficult getting or keeping a firm enough erection to be able to have sex.