The study focused on the analysis of relation between Big Five personality traits of a user and his activity in popular Russian social media Vkontakte. In order to receive Big Five personality trait scores, we asked Vkontakte users to complete a psychological survey and then analyzed data from their personal public social media pages. The purpose of the study was to investigate the relation between social media activity features and users’ level of neuroticism, conscientiousness, extraversion, openness to experience and agreeableness. To perform the task, we used machine learning classification algorithms. © 2018 CEUR-WS. All Rights Reserved.