College time includes lifetime in which young people experience big changes. For most of the students, one of them is changing the place of residence. That kind of change includes roommate relationship that means living with a possibly unknown person. We can say that a roommate relationship is special kind of interpersonal relationship that can have great influence on the entire college experience. Since this is a subject that hasn't been researched in Croatia, the aim of this study was to examine the relationship between personality traits and roommate satisfaction as well as the similarity in personality traits and roommate satisfaction. This research also examined whether satisfaction could be predicted by longevity and personality traits and the difference in satisfaction within gender and longevity of acquaintance. The study involved 70 couples of students that were living together in college dorm Stjepan Radić. They anonymously fulfilled International Personality Item Pool (IPIP 50; Mlačić i Goldberg, 2007), Friendship Roommate Scale (Wiltz, 2003) as well as data about age, gender, roommate longevity and longevity of acquaintance. Conducted t-test showed that there is a statistically significant difference in values of satisfaction of roommate relationship between male and female participants, with women being more satisfied with roommate relationship than men while there was no significant difference in the value of different longevity of acquaintance. The results of Pearson's correlation noted that there is a correlation between satisfaction in roommate relationship and dimensions: extraversion, agreeableness, and conscientiousness. Multiple regression analysis explained 19,5 % of the variance in roommate satisfaction and the factors extraversion, agreeableness, and conscientiousness have proven to be statistically significant predictors of roommate relationship satisfaction. When examining similarity in personality traits and satisfaction, statistically significant correlation is found with the dimension of conscientiousness; satisfaction was connected to participants different scores in the dimension of conscientiousness.