Continuous drying and wetting characteristic of gas-liquid intermittent flows (plug and slug flows) is strongly responsible for erosion-corrosion problems inside the industrial piping systems [1]. For enhancement of erosion-corrosion inhibitor programs in industrial piping systems, accurate measurement of the periodicity of gas and liquid phases is highly essential. This temporal variation of periodicity of gas and liquid phases can be measured in terms of plug/slug frequency. In the present work, effort has been made to measure the plug/slug frequency using LDV (laser Doppler velocimetry). Present technique not only measures the plug/slug frequency but it can also measure the local velocity fluctuations inside the plug and slug flows. Experiments are performed in an air-water two-phase flow test rig for varying the inlet flow conditions of air and water phases in the intermittent regime of flow. First, the methodology adopted for measurement of plug/slug frequency using LDV is explained in detail. Variation of plug/slug frequency in terms of inlet flow conditions is depicted and is compared with the results available in literature. It is found that, plug/slug frequency weakly depends on the superficial gas velocity and is strongly influenced by superficial liquid velocity. The non-dimensional correlation for plug/slug frequency presented in this article is in terms of Strouhal number and liquid volume fraction. Strouhal number in the present work is calculated in terms of mixture velocity thereby considering the influence of both the phases.