Preterm infants require higher calcium and phosphate intake than term infants to facilitate adequate bone growth, but this is rarely met in parenteral nutrition (PN) solution because of the limited solubility of calcium and phosphate. This study aimed to evaluate the solubility of organic phosphate with calcium gluconate in neonatal PN solutions, simulating its clinical use. PN solutions were composed of calcium gluconate at 50 mEq/L and sodium glycerophosphate (NaGP) at 25 mmol/L. Another component included 1% or 4% amino acid and 10% or 20% dextrose. For comparison, PN solution composed of potassium phosphate was also evaluated. Each solution was evaluated using the following methods: visual inspection, light obscuration particle count test, and pH measurement. To simulate the clinical condition, the solution was tested after compounding, after being stored at 25 °C for 24 h, and after being stored at 2°C-8°C for 2 or 9 days and subsequently at 25 °C for 24 h. There was no visual deposition in PN solution using NaGP in any of the concentrations and under any stored condition. The solution fulfilled the criteria of physical compatibility as < 25 particles/mL measuring ≥10 μm in diameter and <3 particles/mL measuring ≥25 μm in diameter. On the contrary, visual deposition was evidently noted in PN solution using potassium phosphate after its formulation, and the particle count significantly exceeded the range of physical compatibility. NaGP and calcium gluconate have significantly good compatibility in PN solution. The use of NaGP in neonatal PN prevents calcium and phosphorus precipitation, hence increasing their supply to preterm infants in meeting their growth requirement.