Comment 13 for bug 219709

I'm having the same problem (fonts changed when importing pdf) and found something that might be useful in fixing this:

The font used in the pdf is called "Unit-Light"; on importing it is changed to "Sans", size is kept.
When you navigate to a text element in the XML Viewer you can see that "font family" is set to "Unit", "-inkscape-font-specification" to Unit-Light. If I set "font family" to "Unit-Light" the text element is displayed with the correct font.
So it seems these style attributes aren't set correctly when importing the pdf - the information on the font is there, but in the wrong place.

The full set of style attributes of one of the text elements is:
"font-size:11.03999996px;font-variant:normal;font-weight:normal;writing-mode:lr-tb;fill:#000000;fill-opacity:1;fill-rule:nonzero;stroke:none;font-family:Unit;-inkscape-font-specification:Unit-Light"

(Some system information: Win XP, Inkscape version 0.48.1)