Coastal Zone Color Scanner (CZCS) results have been used to measure the optical varia-bility of the ocean over large areas. The properties of Jerlov type I waters of areas of the North Atlantic are compared with the types II and III waters of the North Pacific. Several techniques are used to quantify the variability. Radiance variations show the reflectance changes over large and small areas and demonstrate the striking difference between types I and III waters. Color index variations (in which the color index is the ratio of radiances in two spectral bands) have been computed for small areas such as warm core rings and for large ocean areas containing different water masses. Spectral band relationships, which display the radiance at one wavelength against the radiance at another wavelength or against the color index, show a great diversity which makes it difficult to generalize the data. Spectra show the spatial variability of radiance and color for a selection of north-south and east-west tracks covering a range of water types. The results indicate that the color and radiance variations have very diverse characteristics from region to region.