Objective: The purpose of this research was to study the relationships between personality characteristics and emotional intelligence with general psychological health among phenylketonuria patients under treatment living in Tehran. Method:  In this correlation study, 41 patients having no mental or physical disability over 15 years old were evaluated with a demographic questionnaire, Big Five Inventory (BFI, short form), Bar-On's Emotional Intelligence Questionnaire and Goldberg's General Health Questionnaire. Data analyzed by SPSS (V13) and correlation coefficients and linear multivariate regression analysis computed. Results:  findings showed that emotional intelligence is positively correlated with extraversion, openness, conscientiousness and agreeableness, and negatively with neurosis. Also, psychological health was correlated with extraversion, openness and agreeableness, positively and with neurosis negatively. No association was observed between psychological health and conscientiousness. Furthermore, extraversion and agreeableness were able to predict emotional intelligence scores and neurosis predicted general psychological health scores. Conclusion: This study concludes that there exists a positive relationship between extraversion and agreeableness with emotional intelligence and psychological health. Neurosis had a negative relationship with psychological health in phenylketonuria patients under treatment Tehran. Clinical implications have been discussed.