The instant invention relates to the novel soybean cultivar designated CX299c. Provided by the invention are the seeds, plants and derivatives of the soybean cultivar CX299c. Also provided by the invention are tissue cultures of the soybean cultivar CX299c and the plants regenerated therefrom. Still further provided by the invention are methods for producing soybean plants by crossing the soybean cultivar CX299c with itself or another soybean variety, as well as the plants produced by such methods.