This study investigated whether total or partial amnesia following sexual assault increases the risk of developing PTSD symptoms. We retrospectively analyzed medical records of 209 adult patients consulting the Gynaecology Emergency Department at Geneva University Hospitals after alleged sexual assault (2015–2017). Data included presence of amnesia, age, victim-perpetrator relationship, intoxication, gynecological lesions, observed/ reported PTSD symptoms, and psychiatric history. Amnesia was reported in 45.9% of cases, while 76.1% involved intoxication. PTSD-related symptoms (such as anxiety or dissociation) were noted in 37.3% of cases, with no significant difference between those with (32.3%) or without (41.6%) amnesia. Amnesia was more frequent in younger women, often intoxicated, and with unknown assailants. Our results indicate that amnesia after sexual assault is frequent but not associated with a higher prevalence of PTSD symptoms in the acute aftermath but is linked to other factors, such as age and intoxication.