Effect of different initial saturation, seed size and seed loading ratio on crystal size distribution were thoroughly studied to gather more insight in mono-ammonium phosphate batch crystallization and its kinetics. A 300 ml glass jacketed vessel with impeller (turbine with inclined blades) was used as a crystalliser. Supersaturation and temperature were measured online by conductivity meter and thermocouple. A Pt conductivity probe which has range from 2.0 – 19.99 S/m was connected to a conductivity meter. Temperature and conductivity output data were transferred and recorded in a data logger. Batch time is equal to one hour. Lastly, slurry was filtered, washed with acetone and dried. Crystal size distribution was determined by sieving method and it was able to size from 75 µm up to 1400 µm. In addition, a particle size analyser by laser diffraction method which can measure from 0.1 µm to 700 µm is used. Seed loading ratio gives most significant effect on the CSD profiles followed by supersaturation factor and seed size. Supersaturation level not only influences the growth rate but the crystal shape as well. A simultaneous method has been applied in the procedure for the estimation of crystallisation kinetics. The nucleation constant was found to be in the range of 1.0-6.9 x 10⁸ [no/kg s(kg/kg)^b+1] and the growth constant measured was in the range of 3.0-9.4 x 10^-5 [m/s (kg/kg)^g] with the nucleation and growth exponents determined as 2.2 and 1.4 respectively.