A theory has been developed for a microflowmeter of the type described by Benseman. This theory has been found to match the performance of an experimental model of this type and has been used to forecast that instruments of this design could be capable of measuring flows in the range of 0-5 × 10^-3 g cm^-2 sec^-1 with a sensitivity of 0.2 μg cm^-2 sec^-1 per microvolt output.