We present I-band photometry of the soft X-ray transient (SXT) J0422+32 taken during a low-brightness state over two weeks in 1993 October. The object had a mean V magnitude of 19.9, approximately 2mag above its subsequent, presumably quiescent, level of V~22.4. These data revealed a periodicity at 16.18h (significance level>99 per cent), but we could find no evidence for the previously reported 5.1-h period. We cannot account for the physical origin of this 16-h modulation, but suspect that it is related to the brightness state of J0422+32. We show that it cannot be an ellipsoidal effect, as the secondary star would be much brighter than the current minimum. The 5.1-h period could be orbital, with a very late-type (~M0-M5) secondary which is too faint to be observable if the distance is >=1 kpc.