This paper investigates the accuracy of CFD simulation in predicting the nature of multiple plume interactions in a naturally ventilated indoor environment. RANS-based turbulence models; k-ε and RNG k-ε were used to predict the twin plume interaction experiment reported by Kaye and Linden (2004). It was observed that the k-ε turbulence model showed a large discrepancy with measurements while the results obtained from the RNG k-ε model were in better accord with the experimental results. A grid sensitivity analysis of the computational solution also formed part of this study.