Basically, this invention provides for an inbred corn line designated NPCI6621, methods for producing a corn plant by crossing plants of the inbred line NPCI6621 with plants of another corn plant. The invention relates to the various parts of inbred NPCI6621 including culturable cells. This invention also relates to methods for introducing transgenic transgenes into inbred corn line NPCI6621 and plants produced by said methods.