Cerebral palsy (CP) involves trunk impairment, leading to decreased postural control that is an important contributor to problems maintaining daily activities without undue fatigue. Our aim in this research was to determine the effects of trunk impairment on fatigue and balance in children with hemiplegic CP. We included 65 ambulatory children with CP in this cross-sectional study, and we grouped them into those with greater trunk impairment (Group 1, n = 33) and lesser trunk impairment (Group 2, n = 32) according to their scores on the Trunk Imparment Scale (TIS). We assessed their fatique level using the Pediatric Quality of Life Inventory™ Version 4.0 Multidimensional Fatigue Scale (PedsQL-MFS), and their balance ability using the Pediatric Balance Scale (PBS). We found that the PedsQL-MFS parameters, except the general and cognitive fatigue scores, were significantly better for participants in Group 2 than in Group 1; however Group 2 showed significantly higher scores for balance ability than did Group 1 (p <.001). All of the TIS parameters were significantly correlated with sleep/rest fatigue, and PBS scores and trunk coordination were also significantly correlated with general fatigue (p =.013) and cognitive fatigue (p =.003) which are subparameters of the PedsQL-MFS and PBS (p <.001). However static balance was highly and negatively correlated with cognitive fatigue (p <.037).Increased trunk impairment contributed to the exacerbation of fatigue and balance problems in children with hemiplegic CP. Inadequate trunk control was associated with poor sleep and poor resting quality rather than perceived general and cognitive fatigue.