  A sample of 27 sources, catalogued as pre-main sequence stars by the Pico dos
Dias Survey (PDS), is analyzed to investigate a possible contamination by
post-AGB stars. The far-infrared excess, due to dust present in the
circumstellar envelope, is typical for both categories: young stars and objects
that have already left the main sequence and are suffering a severe mass-loss.
The presence of two known post-AGB stars in our sample inspired us to seek for
other very likely or possible post-AGB objects among PDS sources previously
suggested to be Herbig Ae/Be stars, by revisiting the observational database of
this sample. In a comparative study with well known post-AGBs, several
characteristics were evaluated: (i) parameters related to the circumstellar
emission; (ii) spatial distribution to verify the background contribution from
dark clouds; (iii) spectral features, and (iv) optical and infrared colors.
These characteristics suggest that 7 objects of the studied sample are very
likely post-AGBs, 5 are possible post-AGBs, 8 are unlikely post-AGBs, and the
nature of 7 objects remains unclear.
