The research focuses on the relationship of Big Five personality traits and job satisfaction to affective commitment. Data were collected by the means of an online questionnaire on a sample of 445 respondents. Affective commitment was measured by Affective Commitment Scale, job satisfaction was measured by Job Satisfaction Scale and personality characteristics by Big Five Inventory. Hierarchical regression has shown that only extraversion and job satisfaction are related to affective commitment. Agreeableness was also signifficant predictor but only before job satisfaction was added. Mediation effect of job satisfaction on the relationship between agreeableness and affective commitment was confirmed. The relationship of conscientiousness and neuroticism to affective commitment was not confirmed and as expected,openness was not confirmed as a predictor of affective commitment either.