The CO sub(2) and N sub(2)O in the north Indian Ocean were measured and their fluxes were evaluated. Samples were collected from the Arabian Sea and the Bay of Bengal. The water samples were analysed for dissolved oxygen, pH, TCO sub(2) and N sub(2)O. Air samples were collected and analysed for CO sub(2) and N sub(2)O. TCO sub(2) concentration increased steadity towards north in the Arabian Sea however this was not very prominant in the Bay of Bengal. This was attributed to regeneration of CO sub(2) during organic matter decomposition. The slopes estimated for the Arabian Sea were found to be higher than those for other oceanic regions, imphlying a higher rate of N sub(2)O production in this region. The observed horizontal gradients and the deep water concentrations signify quantities of N sub(2)O to be consumed within the sediments. The northern Indian Ocean as a source of CO sub(2) to the atmosphere is poorly quantified. The N sub(2)O data indicate that the vertical diffusion coefficient at the top of the thermocline in the Abrabian Sea is much higher than in the Bay of Bengal. This differential diffusion explains the contrast i the biological productivity between the two areas.