The effect of micro- and nanometer-sized boron particles on boron-potassium nitrate (BPN) ignition composition was investigated in this paper. As a starting point, thermochemical calculations were made to determine the most promising ignition compositions. Both stoichiometric and fuel-rich formulations of BPN were produced to observe the performance variation due to boron content. Particle morphology of boron particles and the surface structure of the ignition compositions were investigated by SEM. The influence of micro- and nanometer-sized boron particles on the calorific value, sensitivity properties, and pressure buildup of compositions were investigated. Sensitivity tests showed that all compositions were safe enough for handling. It was seen that although nanometer-sized boron particles enhanced calorific value and pressurization rate, they did not have a contribution on the maximum pressure level. The maximum adiabatic flame temperature was attained by the stoichiometric composition, but in practice, the stoichiometric composition resulted in much lower performance than the fuel rich composition. Possible reasons for these behaviors of the compositions were discussed in the paper.