[en] The BL Lacertae object PKS 2155-304 was observed with RXTE during 1996 May and November as part of a multiwavelength campaign from radio to TeV energies. The planned sampling for May 1996 consisted of daily 500-sec pointings for 10 days, plus 1 hour per orbit for 2 days to allow a search for X-ray variability on timescales as short as a few minutes; in the actual light curve there are large gaps due to interruption by an unrelated target of opportunity. The missing time was re-scheduled in November 1996, contemporaneous with ROSAT and SAX observations of PKS 2155-304. The PCA light curves exhibit complex flux variations, with short-timescale trends (∼ 1 day or less) superposed on longer trends. The PCA variability amplitude shows no obvious energy dependence. The PCA light curves at both observing epochs are well correlated with those at softer X-ray energies, and no time lags are detected, with limits down to a few hours