This paper describes the observations and data reduction techniques for the version 2.0 images and catalog of the NICMOS Ultra Deep Field Treasury program .
All sources discussed in this paper are based on detections in the combined NICMOS F110W and F160W bands only .
The NICMOS images are drizzled to 0.09/arcsecond pixels and aligned to the ACS UDF F850LP image which was rebinned to the same pixel scale .
These form the NICMOS version 2.0 UDF images .
The catalog sources are chosen with a conservative detection limit to avoid the inclusion of numerous spurious sources .
The catalog contains 1293 objects in the 144 \times 144 \arcsec NICMOS subfield of the UDF .
The 5 \sigma signal to noise level is an average 0.6 \arcsec diameter aperture AB magnitude of 27.7 at 1.1 and 1.6 microns .
The catalog sources , listed in order of right ascension , satisfy a minimum signal to noise criterion of 1.4 \sigma in at least 7 contiguous pixels of the combined F110W and F160W image .