Simultaneous measurements of the pyroelectric (PE) coefficient &lgr; and permittivity &egr; from the PE voltage responses to step ir radiation signals in triglycine sulphate (TGS) are reported as functions of temperature in both the ferroelectric and paraelectric phases. It is shown that the observed lowering and widening of the peaks of &lgr; and &egr;, the appearance of a PE effect in the parelectric phase, and the shift of the &egr; peak to temperatures aboveTccan be explained by the existence of an internal bias fieldEb. The values ofEbcalculated to fit the experimental results vary in different TGS samples from 30 to 150 V/cm.