Abstract Temperature variation of the pyroelectric response Up was studied for NaNH4SO4.2H2O single crystals. In spite of the bulk pyroelectric response veryfied by flux modulation frequency dependence of Up in the ferroelectric phase, a small, frequency independent pyroelectric response was observed in the paraelectric phase up to ∼ 200 K. Moreover, the pyroelectric response is accompanied by Barkhausen pulses. The high temperature tail of Up(T) is attributed by us to the water defects in the crystals.