This paper describes measurements of noise from cavitating flow over a hydrofoil. Cavitation was generated on a hydrofoil in the presence of a separated laminar boundary layer on the one hand and of a fully turbulent attached boundary layer on the other. The turbulent boundary layer was formed down‐stream of a trip which was positioned near the leading edge. The noise is shown to depend on the type of cavitation produced. Dimensionless spectral densities of the sound are shown for each type of flow. For the cavitation associated with turbulent boundary layer development, the dimensionless spectrum is interpreted in terms of the observed single‐bubble motions in the experiment.