The impact of electrical stressing on the microwave performance of the SrTiO3 films deposited onto different substrates (MgO and LaAlO3) by pulsed laser deposition has been investigated. The most important characteristics of the tunable microwave components like tunability and loss tangent have been monitored. It has been found that electrical degradation effects, being sensitive to the device operating conditions and ferroelectric film properties, are large enough to affect the performance of ferroelectric-based tunable microwave devices within the expected operating time.