A liquid-liquid two-phase flow based segmented microfluidics system comprising of a simple microfluidic junction and a PTFE microbore tube to synthesize BaSO4 nanoparticles is reported. The system is shown to be robust enough for continuous operation without any chocking. The effects of different operating parameters such as A/O ratio, initial concentration of precursors, precursor molar ratio and flow velocity on particle size and polydispersity index are studied. The above-mentioned parameters are important in synthesizing nanoparticles of precise and controlled size. Three different microfluidic junctions are evaluated for their influence on particle size and polydispersity index. Under optimum conditions, small and monodispersed BaSO4 nanoparticles (particle size and polydispersity index being 65 nm and 0.10, respectively) could be synthesized continuously using a cross microfluidic junction and microbore tube.