Trickle-bed reactors are widely used in industrial high pressure operations (up to 30 MPa). The knowledge of catalyst wetting efficiency as a function of operating conditions is needed for relating laboratory and pilot scale reactor data to large scale reactor operation. The available predictions of the wetting efficiency rest on data collected at atmospheric pressure. In this study a phenomenological analysis has been developed to relate the wetting efficiency with operating conditions such as reactor pressure, gas and liquid how rate. Experimental data for the wetting efficiency at high pressure have been obtained via a tracer technique. The data support the developed model which can be expressed by the following correlation : eta(CE) = 1.104 Re-L(1/3) [1+[(Delta P/Z)/rho(L)g]/Ga-L](1/9). This correlation is also in good agreement with the data correlated previously at atmospheric pressure and provides the means for assessing liquid-catalyst contacting at all operating pressures.