The principal motivation for undertaking a research process was the fact that, in the literature of the subject, there is still less than sufficient number of studies relevant to the subject of the influence exerted by the selected aspects of the organisation of mass events upon the security and the satisfaction of participants in them. The research process was conducted in two stages, in the years: 2016 and 2017, on the group of 3,820 participants in Rzeszow Juwenalia. In the publication, it was attempted as well to verify the research hypotheses enumerated hereinbelow: a presumption that the gender, the attended year of studies, and also attending a given institution of tertiary education, do not exert influence upon the assessments of Rzeszow Juwenalia in the context of the feeling of security of participants, and also the assessment of the actions of services ensuring the security of the event venue by them is adopted; another presumption, that the assessment of Rzeszow Juwenalia in the context of the feeling of security of participants, and also the assessment of the actions of services ensuring the security of the event venue by them, is not, to a significant degree, different in studied periods of time, was adopted as well. The research process which was conducted made it possible to verify the adopted research hypotheses, and also to determine what factors make it possible to grasp the difference between the perception of the selected aspects of the organisation of an event by participants in it.