Spherical hydroxyapatite (HA) nanopowder was synthesized at a rate of 20 g/h from HA sol using a 30 kW inductively coupled radio frequency plasma spray system. The HA sol was axially fed with a water-cooled steel probe in the lower temperature region of the supersonic plasma nozzle, which helped in HA phase stabilization. The HA powder was synthesized at plate power between 19 and 28 kW. Particle size, surface area, particle morphology, and phase composition of the synthesized powder were evaluated using transmission electron microscopy, BET specific average surface area, X-ray diffraction (XRD), and Fourier-transformed infrared spectroscopy. The synthesized nanopowder was spherical in nature, with the particle size ranging from 30 to 70 nm. The increase in plate power resulted in a decrease in particle size. XRD results indicated HA to be the primary phase along with phase decomposition products, such as tricalcium phosphate and calcium oxide. Cytotoxicity behavior was studied using human osteoblast cells to ensure biocompatibility.