A quasi-continuously pumped picosecond oscillator-amplifier laser system based on two identical 2.4% Nd:YAG slabs in a single bounce geometry was developed and investigated. The oscillator was passively mode locked by the multiple quantum well saturable absorber inserted into the resonator in transmission mode. Output train containing 7 pulses with total energy of 900 μJ was generated directly from the oscillator. Single pulse with energy of 75 μJ, duration of 113 ps and Gaussian spatial profile was cavity dumped from the resonator and amplified by the single pass amplifier to the energy of 830 μJ. Comparison with our previously reported data obtained with similar system based on Nd:GdVO₄ shows advantage of using highly doped Nd:YAG for generation of sub-millijoule pulses in one hundred picoseconds range, which might be interesting in many applications.