This study investigated how aspects of perfectionism in athletes (N = 388) related to the fears of failure proposed by Conroy et al. (2002), and how perfectionism and fears of failure predicted positive and negative affect after imagined success and failure in sports competitions. Results showed that perfectionistic personal standards showed a negative relationship with fear of experiencing shame and embarrassment and a positive relationship with positive affect after success, whereas perfectionistic concern over mistakes and perceived parental pressure showed a positive relationship with fear of experiencing shame and embarrassment and with negative affect after failure. Moreover, fear of experiencing shame and embarrassment fully mediated the relationship between perfectionistic concern and negative affect and between coach pressure and negative affect. The findings demonstrate that fear of experiencing shame and embarrassment is central in the relationship between perfectionism and fear of failure, and that perfectionistic concern about mistakes and perceived coach pressure are aspects of perfectionism that predict fear of experiencing shame and embarrassment and negative affect after failure.