The design of subminiaturized natural fragment warhead is based on the analysis of its effectiveness against target personnel. Toward this end, the personnel incapacitation probability suggested by Sperrazza and Kokinakis was used. The effectiveness of various natural fragment warhead designs was analyzed by altering the fragment mass, velocity, number, and the target distance. A preliminary optimal design value of the natural fragment warhead in a subminiaturized missile was suggested, which was greater than the threshold value of the fragment mass to cope with air resistance. We also determined that the appropriate fragment mass was about 2.1204 × 10^-4 kg (3.3 grain) in case of a subminiature warhead. This work facilitates the development of final optimal design stage of the natural fragment warhead in a subminiaturized missile and can also be utilized for the analysis and design of different types of fragment warhead.