Introduction: Among determinants of posttraumatic growth the essential role play cognitive processes, including event related rumination. The study aimed to establish whether in adolescents struggling with cancer diseases there is a relationship between the level of ruminations and the severity of personal growth.

Material and methods: Results of 50 adolescents, aged 14–18 years (M = 15.14, SD = 1.34) were analyzed. The majority of respondents (66%) were boys. The Event Related Rumination Inventory and the Personal Growth Questionnaire were used in the study.

Results and conclusions: The results indicated the presence of positive changes in examined adolescents. Larger changes were related to self-perception and appreciation of life than relations with others. Both types of ruminations (intrusive, deliberate), were positively linked to the level of personal growth, but stronger associations concerned intrusive ruminations. This type of rumination proved to be a predictor of personal growth and all three of its dimensions. Encouraging adolescents struggling with cancer to ruminate may contribute to occur of growth after trauma.