Carbon nanoparticles were synthesized via laser ablation of graphite target in distilled water. The particle sizes of carbon nanoparticles were investigated as a function of laser energy: 1, 1.5, and 2 J/pulse. Using water as a matrix during synthesis is another potential way to control the particle size. The mean size increases when increasing the laser energy. The particle morphology is a globular shape. The sizes of the nanoparticle were evaluated from both SEM image analysis and Scherrer’s equation. The sizes from the equation are smaller than those obtained from SEM, which indicates that the particles are polycrystallines.