Background: The influence of sleep quality in sleep paralysis has not been widely documented in medical students, although they are exposed to high academic loads in undergraduate studies. Aim: To determine the association between sleep quality and paralysis in medical students from Paraguay. Methods: Analytical cross-sectional study in first- and second-year medical students at Universidad del Pacífico, Paraguay in 2018. The questionnaire was self-administered and consisted of socio-educational data (age and sex), index of Pitsburgh sleep quality and self-reported sleep paralysis. Simple and multiple regression models were built, estimating prevalence ratios. Results: Of 329 medical students, the majority were male (34.7%) and the median age was 19 years. 48.3% and 47.1% presented poor quality of sleep and sleep paralysis; respectively. Poor sleepers had a 40% higher frequency of repor...