A method is proposed for automatic tuning and stabilization of the energy threshold in scintillation detectors by maintaining the constancy of the average detector counting rate from Γ rays of natural radiation background or cosmic rays. Stabilization is automatically performed by controlling the photodetector supply voltage, which makes it possible to stabilize the detector threshold with an error of 0.73–2.40%, depending on the used circuitry. The stabilization electronics for scintillation detectors with avalanche multipixel photodiodes and photomultipliers is described. A circuit ensuring the increased precision of threshold stabilization is also proposed.