On the basis of the experimental results along with those available in the literature (1678 experimental data from five liquid systems, covering 10 different packings, from three sources) with a wide range of variables, a generalized approach is developed to identify the flow regime transitions viz., bubble flow, dispersed bubble flow and pulse flow in cocurrent two-phase (gas-liquid) upflow through packed beds. New correlations for the estimation of frictional pressure drop involving all the fundamental and operating variables are also presented for the three regimes of operation. This present correlations are more accurate than those previously reported.