Poly(ethylene terephthalate) (PET) nanocomposites with a newly synthesized organomica (C16BIMD-Mica) were obtained by using the in situ interlayer polycondensation of ethylene glycol with dimethylterephthalic acid. The PET hybrids were melt-spun to produce monofilaments with various organoclay contents and draw ratios. The thermomechanical properties and morphologies of the PET hybrid fibers were determined using differential scanning calorimetry, thermogravimetric analysis, wide angle X-ray diffraction, electron microscopy (SEM and TEM), and a universal tensile machine. The XRD analyses and TEM micrographs showed that the levels of exfoliation and intercalation could be controlled by varying the clay content. The thermomechanical properties of the PET hybrid fibers were found to be better than those of pure PET fibers.