We calculate the chromatic dispersion of rectangular geometry waveguides and focus on the conditions for obtaining zero chromatic dispersion at a wavelength of 1.55 ?m. We consider single-mode waveguides fabricated from six distinct compositions of silica-based materials whose dispersive characteristics are modeled by use of a Sell- meier relation. Our analysis takes account of the two transverse dimensions of the guiding channel and provides for a determination of the dispersion coefficient ?" as a function of the values of both dimensions. The results allow us to compute a spectrum of values of the two transverse widths for which the total dispersion is zero. By definition of an effective mode field diameter for a channel waveguide we are able to discuss the end-to-end coupling of such a waveguide to a commercial single-mode fiber.