The optimum conditions for rapid mixing of two fluid streams in turbulent pipe flow were investigated for different velocity ratio and different angles of jet injection. The optimum velocity ratio and optimum injection angle were determined by comparing the mixing characteristics for one phase flow (water-water) and two phase flow (Water with Salt Solution). The mixing characteristics and optimum conditions are compared between experimental results and asymptotic solution ( theoretical results ) for one phase flow (water-water). The mixing characteristics and optimum conditions are also compared between one phase flow (water -water) and two phase flow (water with salt solution). The following things were concluded from the present work: (1) When the jet velocity is too low there will be insufficient penetration into the main flow while if the jet velocity is too high there will be too much penetration. (2) When the branch pipe faced downstream, mixing was poorer than with a T-Junction but when branch pipe faced upstream, excellent mixing was obtained. (3) For a two phase flow the mixing length decreases in comparison to one phase flow.