A rapid new method for preparation of monodisperse InP-nanocrystals was developed. A highly reactive indium precursor and tris(trimethylsilyl)phosphine (TMS)3P was reacted within a weakly coordinating solvent in the presence of a supporting protic agent. The yielded InP-nanocrystals had a very narrow size distribution without any size selection process. The precursor and ligand effects were considered as critical factors in control of nucleation and crystal growth process. Different ligands were introduced to study the reaction mechanism. The new method not only yielded the "best" InP-nanocrystals so far, but also includes the potential for preparation within a continuous flow reactor, because the utilized ester is liquid at room temperature.