This study investigated how the emotional wellbeing of children with congenital heart defect (CHD) hospitalized for heart surgery was expressed in self-drawings before and after their surgical treatment. A sample of 293 children produced self-drawings (hospitalized n = 168, non-hospitalized n = 125). The results indicate significant differences between drawings by hospitalized compared to non-hospitalized children, including size, color and omission of body parts. These differences were interpreted in line with previous analyses of projective drawing. We conclude that self-drawing evaluation is a useful tool to reveal insights into emotional wellbeing, promoting safe and easy communication.