We measured perceived changes in chromaticity at different eccentricities in the nasal visual field of nine colour normal observers. An asymmetric matching procedure was used in which a probe stimulus presented at 1° was compared with the peripheral test stimulus. Perceived shifts in hue in the periphery appear to be controlled by different mechanisms to shifts in saturation. Systematic changes in hue are evident across colour space and these are independent of stimulus size and similar in different observers. Saturation changes are not so well defined in colour space, they are highly dependent on stimulus size, and are variable in different observers. In this paper we report the interpretation of these observations in terms of a cone-opponent model. We find that the perceived shifts in chromaticity that occur in the periphery are largely attributable to decreased (L-M) activation. Although there are minor individual variations, activation in the S-(L+M) pathways remains relatively unchanged up to eccentricity of 20°. This discrepancy between the two pathways reflects the retinal anatomy, indicating the two pathways use different strategies for the construction of their respective receptive fields.