Children with severe cerebral palsy (CP) often have lower mineral intakes than healthy children. It is unknown if their lower nutrient intakes are adequate to meet their needs. The objective of this study was to examine the sodium, potassium, phosphate, and fluid status of primarily tube-fed nonambulatory children with severe CP. The design consisted of a cross-sectional exploratory study and a clinical trial of sodium supplementation. Nutritional status was determined among primarily tube-fed children (aged 2 to 17 years) with CP based on blood and urine samples, anthropometry, and 3-day food records. Mineral and fluid status was evaluated by a nephrologist blind to nutrient intakes. Twenty children supplied food records, blood samples, and anthropometric measurements, and 16 supplied urine samples. Six (37.5%) of those who provided urine samples were considered possibly dehydrated, as urine osmolality was >600 mmol·kg(-1). Six (60%) of the 10 children with satisfactory fluid status (low urine osmolality) were considered to have a possible dietary sodium deficiency based on a very low urine sodium concentration (<20 mmol·L(-1)). Those considered to have a possible dietary sodium deficiency had a significantly lower sodium intake (48% ± 15% Adequate Intake (AI)) compared with those considered sodium sufficient (73% ± 20% AI) (p = 0.031). One child was considered possibly phosphorus deficient, but none was assessed as likely potassium deficient. The conclusion was that sodium deficiencies were likely prevalent among the children. The findings from this small observational study suggest that sodium intakes for tube-fed children with CP should be maintained near the AI for their age. Hydration status of children receiving hypercaloric formulas should be monitored.