This experimental study addressed condensation heat transfer coefficient of R-134a flow inside corrugated tube of different inclinations relative to horizon, ?. The experimental apparatus was basically a vapor compression refrigeration cycle equipped with all necessary measuring instruments. The test condenser was a cross flow heat exchanger in which R-134a vapor flowing inside the inner corrugated copper tube was condensed by rejecting heat to the cooling water flowing in annulus. The length of this test section was 700 mm. The empirical data was taken in the process of R-134a vapor condensation in seven different inclinations of test-condenser within the angular limit of -90? to +90° and four different mass velocities of 87,142, 197, and 253 kg/s.m2. The analysis of collected data showed that the change in tube inclination has a significant effect on condensation heat transfer coefficients. This effect is more pronounced at low mass velocities and low vapor qualities. At low mass velocities and low vapor qualities, the highest coefficient of condensation heat transfer is achieved for the tube with inclination angle of ?=+30?, which is %41 more than the least heat transfer coefficient gained for the tube with ?=-90? ,while the average heat transfer coefficientin test condenser with ?=+30° is 31.4% more than that for ?=-90°. Also, at low vapor qualities condensation heat transfer coefficient for ?=+30°, is 11. 4% more than that for horizontal tube, while the average heat transfer coefficient,, in test condenser with ?=+30° is 6% more than that for horizontal tube. In fact, interfacial shear stress is dominant at high vapor velocity and high vapor quality, while at low vapor qualities, the vapor phase motion is slowed down and this would result in decrease of interfacial shear stress and consequently lower inertia forces near the wall. Therefore, the effect of gravity force on the condensation of R-134a flow at low vapor qualities is more considerable. For all mass velocities, the highest average heat transfer coefficient is belonged to the tube with ?=+30°. The other point is that the tube with an inclination of ?=-90° has the least heat transfer performance. In downward vertical flow, since the interfacial shear stress and the gravity are acting in the same direction, the flow pattern will remain in annular status. Besides, the condensed liquid on the wall is thickened moving towards the flow direction which leads to an increase in thermal resistance and consequently a decrease in heat transfer. Likewise, the interfacial turbulence will be minimized which is also another reason for the poor heat transfer performance. For the vertical upward flow, ?=+90°, due to interfacial turbulence at low vapor qualities, there is better heat transfer performance in comparison to downward vertical flow. This result is reversed at high vapor qualities and heat transfer performance for the downward vertical flow is better than the upward one. This could be due to the better condensation on corrugated surface of the tube in comparison with the vertical upward flow. Finally, based on the present experimental results, the new empirical correlation is developed to predict the condensation heat transfer coefficients in corrugated tubes. This correlation predicts the experimental data within an error band of ±9%. Key words:Heat transfer increase, Condensation flow, Corrugated tube, Tube inclination