This study aimed to evaluate the mediating role of pessimistic views about the working world in the relationship between proactive personality and career adaptability in emerging adulthood. Using a regression analysis based on the bootstrap method, we tested whether pessimistic views about the working world have a mediating role in the effect of proactive personalities on an individual's their career adaptability. The study group consisted of 310 participants who were in the emerging adulthood stage. The results showed that pessimistic views about the working world mediated the relationship between proactive personality and career adaptability. These findings were discussed within emotional factors related to careers. Based on the research findings, theoretical and practical suggestions were presented, especially for career pessimism in emerging adulthood. [Paper presented at the International Psychological Counseling and Guidance Congress (22nd, Mus, Türkiye, Oct 2019).]