A novel scaling law for the tip vortex cavitation (TVC) noise was determined from the physical basis of the TVC, employing the Rankine vortex model, the Rayleigh-Plesset equation, the lifting surface theory, the boundary layer effect, and the number of bubbles generated per unit time (N_0 ). All terms appearing in the final derived scaling law are well known 3D-lifting surface parameters, except for N_0. In this study, the dependence of N_0 with inflow velocity and hydrofoil dimension is investigated experimentally while trying to retain the same TVC patterns among different experimental conditions. Afterwards, the effect of N_0 on TVC noise is analyzed. Optimal TVC observation conditions (developed TVC conditions) are determined from consideration of cavitation number and Reynolds number of two comparable conditions. Two geometrically scaled hydrofoils are concurrently placed in a cavitation tunnel for hydrofoil size variation experiment. Images taken with a high speed camera are used to count N_0 by visual inspection. The noise signals at all conditions are measured and an acoustic bubble counting technique, to supplement visual counting, is devised to determine N_0 acoustically from the measured noise data. The broad-band noise scaling law incorporating N_0 and the International Towing Tank Conference (ITTC) cavitation noise estimation rule for hydrofoil are both applied to estimate the TVC noise level for comparison with the measured noise level. The noise level estimated by the broad-band noise scaling law accounting for the acoustically estimated N_0 gives the best agreement with the measured noise level.