Background: The research presented here was designed to look for possible relationships between personality traits, including temperament, work ethic components and workaholism. Workaholism, i.e., work addiction was conceptualized as obsession and compulsion to work and excessive work. Material and Methods: The NEO-Five Factor Inventory and the Emotionality, Activity, Sociability-Temperament Survey were used to measure personality, including temperament. Work ethic was measured using the Multidimensional Work Ethic Profile, and workaholism was measured using the Dutch Work Addiction Scale. The survey was conducted at 2 time points 5 weeks apart. Predictors (personality, work ethic) were examined first and workaholism was examined after 5 weeks. A sample of 211 employees from various Polish organizations was surveyed. Results: The results of the canonical analysis indicate that negative emotionality, a tendency to react with emotions such as dissatisfaction (distress), and selected components of work ethic – namely, perceiving work as a moral obligation, work centrality, aversion to wasting time, and, to a lesser extent, the valuation of hard work – are significant predictors of work-related obsession, compulsion, and excessive work involvement. Activity also emerged as a significant, though weaker, predictor of workaholism. Low agreeableness was found to be a weak predictor of workaholism. Conclusions: The results of the study show that high arousability, i.e., the ease of responding with emotional arousal, and beliefs that value work, such as viewing work as a value and a duty, are important in predicting levels of workaholism. High activity, understood as vigor and sociability, as well as low agreeableness, are weaker predictors of work addiction. Med Pr Work Health Saf. 2025;76(5)