We present period determinations of the microvariability of the six luminous blue variables AG Car, HR Car, 164 G Sco, S Dor, R 127, and R 71. In total, we were able to determine 22 periods in these stars, ranging from 18 days up to 195 days. All stars have period changes by up to a factor 4 within time scales of a few hundred days. For all stars the amplitude of the pulsations in V increases with increasing periods. The slope of the correlation between the amplitude and the period decreases with increasing luminosity.