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Alternating current voltage (60 cycles/sec.) was found to increase boiling heat transfer rates and prevent film boiling for deionized water under forced convection at essentially ambient pressure. Steam was used to supply heat to the interior wall of a 0.292-in. thick annulus, and voltages up to 5,000 v. were impressed across the region of vapor formation. The highest heat transfer rates reached were approximately twice the normal nucleate boiling peak. The application of voltage increased the boiling heat transfer over the entire range tested—mass flow rates up to 5.2 × 105 lb./hr.-sq.ft. and exit qualities up to 4% by weight vapor. Data obtained from tests in which the external wall of the flow annulus was heated indicated an increase in heat flux up to 2,000 v., followed by a decrease in heat flux at voltages above 2,000 v.