Brain Fag Syndrome (BFS) which was first described by Raymond Prince in Nigeria in 1960, has continued to be studied. It is a culture bound syndrome found in Africans who are engaged in intellectual activities. It constitutes an impediment to the goal of studentship as it may lead to student wastage and or school dropout. Some theories have been put forward to explain the aetiology of BFS. Prince put forward the Forbidden Knowledge and the Ego Energy theories while Morakinyo Olufemi propounded the Psychophysiological or Circular Theory which links BFS to stimulant use. Most appealing is the Psychophysiological Theory, which could be subjected to empirical study. However, there is a dearth of study to link BFS to stimulant use. The aims of this cross-sectional study were; to determine the prevalence of BFS and stimulant use among undergraduate students at the University of Benin, determine any association between the two, to know the socio-demographic factors associated with BFS and to identify factors that may contribute to BFS among students who use stimulants. Multistage sampling technique was used to select five hundred, 300-level students from 7 of the 13 Faculties in the University, but 482 questionnaires were analysed due to attrition. Prevalence of BFS and past 30 days general stimulant use among the respondents were high (42.9% and 39.4% respectively). There was a statistically significant association between BFS and use of stimulants by the respondents. The study supported the Psychophysiological theory because BFS was common among the respondents that used stimulants. There was no significant difference between the socio-demographic characteristics of students who had BFS and those who did not. The study showed a significant positive correlation between general psychiatric morbidity and BFS, in that BFS was significantly common among the respondents who were GHQ positive. Gender and general psychiatric morbidity were significantly associated with the respondents who used stimulants and came down with BFS. BFS was commoner among females than males who used stimulants, and among the students who used stimulants that were positive on the GHQ. Consequent upon the earlier mentioned findings, Nigerian undergraduate students may mind the use of stimulants during studies to forestall their coming down with BFS. Undergraduate students in Nigeria may learn the right study habits that would not need the use of stimulants to stay awake. In addition, mental health service provision as a part of the University health services rendered to the University community, for early detection and treatment of such problems as BFS among the undergraduate students. This could minimize BFS and the rate of dropout among the students, for the good of the Nigerian society.