A polarized 13C target has been developed and used to measure spin observables for 500-MeV p-13C elastic scattering. The material was ethylene glycol, 13C2H6O2, enriched to 99% in 13C. Both the 13C and 1H spins were dynamically polarized in a 3He refrigerator at 2.5-T magnetic field. The polarization of both species was measured by using the NMR thermal equilibrium calibration technique. In addition, the polarization of 1H was independently measured by p-p scattering. We describe the target and report on the polarizations obtained and the dependence of the polarizations on integrated beam intensity.