The production of carboxylic acids from renewable resources using fermentation technology is still restricted because of the limitations in the recovery of the product from fermentation broth. In the present study, the reactive extraction of valeric acid (0.05-0.13 M) from its aqueous solution with tributyl phosphate (TBP) as an extractant and toluene and kerosene as diluents is studied. The effect of valeric acid concentration in aqueous solution is observed through the distribution coefficients. It has been observed that the distribution coefficient value is increased with the valeric acid concentration for a fixed concentration of the extractant in both the diluents. A similar trend is also observed for the extractant concentration in the diluents at a fixed valeric acid concentration. The values of the distribution coefficient were found to be higher for kerosene than those for toluene. The performance of the two diluents was compared based on the number of extractant molecules reacted per mole of acid, n, and the extraction equilibrium constant, K-E. The values of n and K-E are found to be greater for kerosene as compared to toluene. It is concluded that kerosene is a better diluent with TBP than toluene for the extraction of valeric acid.