Accurate wavelength scanned four-wave mixing (FWM) measurement results in an optical fiber are presented with two tunable laser sources near the dispersion-zero wavelength of the fiber. By comparing the measured FWM data with a simple analytic expression, we have demonstrated that important linear and nonlinear optical properties such as zero-dispersion wavelength, dispersion slope and nonlinear refractive index of the sample fiber. Highly accurate and repeatable measurement results for a sample fiber are presented. Temperature-dependent change in the chromatic dispersion of a fiber is also investigated.