A Ni-polymethacrylate pellet of diameter 1·4 cm, thickness 0·114 cm, cross-sectional area 1·539 cm 2, weighing 470 mg and prepared under a pressure of 8 tons PSI was used for electrical conduction measurements in the temperature range 292–369 K. The electrical behaviour of the sample results from two distinct conduction mechanisms. Ohmic conduction is observed up to 325 K and 300 V. Ionic conduction is operative because of (i) the high value of activation energy in the low ( T < 325 K) and high (325 < T < 369 K) temperature regions in contrast to our investigation of Pd-polymethacrylate, (ii) the appearance of reverse current by reversing the polarity of the applied voltage, (iii) current-voltage hysteresis and (iv) a time-relaxation phenomenon. At T < 325 K, the ionic conduction is due to weakly trapped impurity ions, whereas at 325 < T < 369 K, H + ions are the main source of ionic conduction. The material exhibits semiconducting behaviour in the temperature range under investigation.