Comet C/2011 Q4 (SWAN) was discovered on the 4th September, 2011, through images taken by the Solar Wind ANisotropies (SWAN) Lyman-alpha all-sky camera onboard the SOHO satellite. The preliminary orbital elements of the comet indicate a perihelion passage on the 21st September, 2011, at a distance of 1.1 AU from the Sun.