Rosemary's Baby along with Repulsion and The Tenant create Roman Polanski's Apartment Trilogy about the horrors and psychosis that lurk in the ordinary walls, in peepholes, under the carpets and behind the furniture. While The Tenant has a male protagonist who moves in the new apartment and has to deal with bizarre neighbors and creepy occurrences - like finding tooth in the wall - both Rosemary's Baby and Repulsion have delicate, timid blondes as their heroines.
While Rosemary struggles with her pregnancy after she moves in to new building and grows increasingly worried of new neighbors and distant from her husband, Carol is left alone in her apartment after her sister leaves for holiday with her boyfriend. Young repressed girl's sanity starts to collapse in the face of her solitude. Both films are very creepy and subjective - you constantly wonder what is real and what is a hallucination, what's a threat and what's just a distorted perception of the troubled heroine.