Four methods are described for measuring chromatic dispersion: (a) phase shift, (b) spectral group delay in the time domain, (c) differential phase shift, and (d) interferometry. Methods A, B, and C apply to the measurement of chromatic dispersion of the following fibres over a specified wavelength range: class A1 graded-index multimode fibres; category A4f, A4g and A4h multimode fibres; and class B single-mode fibres (all categories). Method D applies to the measurement of chromatic dispersion values of single-mode fibres categories B1, B2, B4 and B5 over the 1 000 nm to 1 700 nm wavelength range. The main changes in this second edition concern the addition of a new Annex E on chromatic dispersion fitting and the applicability to A4 fibres.