Assessment of muscle functional state in children with cerebral palsy (CP) is an important aspect of developing personalized rehabilitation programs. The combined use of bioelectrical impedance analysis (BIA) and electromyography (EMG) makes it possible to optimize the diagnosis methods and improve therapy efficacy. The study aimed to compare groups of patients with CP (n = 91) and healthy children (n = 94) using BIA and EM. Based on the BIA data the patient were divided into four categories: A — increased body fat percentage (BFP), reduced skeletal muscle mass (SMM); B — decreased BFP, increased SMM; C — increase in both indicators; D — decrease in both indicators. The analysis considered gender and average age of each group. Patients with CP (M: BFP p = 0.0001, SMM p = 0.0015; F: BFP p = 0.0003, SMM p = 0.0009), regardless of gender, showed similar distribution: the majority belonged to categories C (М — 50%; F — 46.9%) and D (М — 32.5%; F — 28.1%). The group of healthy people (М: BFP p = 0.0005, SMM p = 0.0004; F: p = 0.0013, p = 0.0008) showed the opposite trend: the majority of patients belonged to categories А (34%) and В (34%). In the group of females, the majority of patients belonged to group B (40.4%), group C ranked second based on the number of patients (27.6%), which was considerably lower, than in the group of children with CP. The phase angle values were also traced: there were significant differences (p < 0.05) with superiority of categories А and В, regardless of the group and gender. The EMG data also showed superiority of categories А and В when considering turn amplitudes. A conclusion was drawn about the skeletal muscular function differences in the specified categories of patients.