In this work, characterization of polymer matrix composites was carried out. Thermoplastic polymers were used as a matrix. Nondestructive Young's modulus values were compared with the destructive values. Differences between the destructive and nondestructive values are less than 10%. Reinforcements increased Young's modulus. The principal strain values of the glass fiber-reinforced polymethylmethacrylate (PMMA) composites were higher than that of graphite-reinforced PMMA composites. Radiography and tomography methods were used for the characterization. Specimens consisted of homogeneously distributed reinforcements. Imaging behavior was appropriate. There are no cracks or pores according to radiography. Specimens consisted of homogeneously distributed reinforcements.