We present the data and preliminary analysis for a series of 90 ROSAT HRI and two ASCA observations of the broad-line radio galaxy 3C 390.3 .
These data were obtained during the period 1995 January 2 to 1995 October 6 as part of an intensive multiwavelength monitoring campaign .
The soft X-ray flux in the ROSAT band varied by nearly a factor of four during the campaign , and the well-resolved light-curve shows several distinct features .
Several large amplitude flares were observed , including one in which the flux increased by a factor of about 3 in 12 days .
Periods of reduced variability were also seen , including one nearly 30 days long .
While the HRI hardness ratio decreased significantly , it is apparently consistent with that expected due to the detector during the monitoring period .

The two ASCA observations were made on 1995 January 15 and 1995 May 5 .
The 0.5–10.0 keV spectra can be adequately described by an absorbed power-law .
There is no evidence for a soft excess in the ASCA spectra , indicating that the ROSAT HRI is sampling variability of the X-ray power-law .
A broad iron line was observed in a longer 1993 ASCA observation , and while there is statistical evidence that the line is present in the 1995 spectra , it could not be resolved clearly .
There is evidence , significant at > 90 % confidence , that the photon index changed from 1.7 to 1.82 while the flux increased by 63 % .
The spectral change can be detected in the spectra below 5 keV , indicating that the origin can not be a change in ratio of reflected to power-law flux .
A compilation of results from ASCA and Ginga observations show that on long time scales the intrinsic photon index is correlated with the flux .