The motion of the Taylor bubbles in vertical and near-vertical tubes was investigated. The non-invasive measurements were conducted by using a high-speed motion analyzer. For the vertical slug flow, the coefficient C1 was found to be very close to the ratio of the maximum velocity to the average velocity in the profile. For the inclined slug flow, the value of C1 is smaller than that for the vbertical case because the nose tip of the Taylor bubble usually deviates from the centerline. The drift velocity is increased with the decrease of inclination angle. Based on the theoretical analysis and experimental data, the bubble velocity correlations were obtained. The results are in good agreement with the available data.