Background: Parents of children suffering from congenital heart disease experience high levels of stress and negative emotions. Therefore, recognition of parents’ emotional states and their ways of coping with it is becoming more and more important. Methods: The study group consisted of 154 parents of newborns and infants with cyanotic congenital heart disease, before and after cardiac surgery (partial or full). To assess parental negative emotions, the level of stress, and strategies of coping with it, standardized questionnaires, such as HADS-M, PSS-10, and COPE, were used. Results: Stress levels in parents were high and associated with negative emotions (anxiety, depression, irritability), as well as the choice of non-constructive coping strategies, which was observed especially in younger parents. Conclusions: Assessing parents’ stress levels and ways of coping with stress can improve family functioning and provide better development conditions for the child.