The poster uses a minimalistic style with dull colors like black and light gray that create a creepy and dismal atmosphere appropriate for a horror genre film. The main image depicts a possessed-looking girl smearing blood on a wall in a dimly lit scene, giving insight into the film's storyline. Text at the top in white contrasts with the black background to draw attention and introduce the producer. The large centered title "Sinister" makes the film name easy to notice and want to learn more. Additional text provides a tagline that hints at the male antagonist and generates interest in the story.