Ich würde das gar nicht sagen (das klingt sehr deutsch übersetzt), sondern 'I feel guilty for having done sth'

... oder 'I feel bad for...'

You may have a bad conscience for something you have done (or have not done). You may also have a bad conxcience about something you did (or did not do).

I think "feeling guilty" or "having a bad conscience" do not express the same feelings. In German, "sich schuldig fühlen" or "ein schlechtes Gewissen zu haben" are not the same either, or am I mistaken?

It's just that in almost ten years living with a Brit (and talking to British friends, obviously), I've never heard anybody say 'I've got a bad conscience'. It just doesn't sound very idiomatic to me. (But please convince me otherwise, all you native speakers out there, if I'm wrong).

I agree with Gibson. "A bad conscience" sounds unusual to me. Sounds like a literal translation of the German. It may exist, but in this context at least, I'd say "someone has a guilty conscience" for cheating on their exam, etc.

to feel guilty for something...
has different connotations in English than sich schuldig fühlen does in German. For example,
I felt guilty after eating that last piece of chocolate cake.
is perfectly normal English, but I don't think you would use sich schuldig fühlen in German for this context, right?

Ich würde in der Regel to feel guilty = ein schlechtes Gewissen haben übersetzen. Die Formulierung sich schuldig fühlen ist sehr viel stärker; ihre inflationäre Verwendung in letzter Zeit empfinde ich als Anglizismus.

Definitely "feel guilty" - "bad conscience" is not English. You can say you have "something on your conscience", or that your "conscience is bothering you", something is "weighing heavily on your conscience", etc., but the most common expression is simply to feel guilty.

to have pangs of conscience

I'm familiar with the expression to have a guilty conscience.

I'd use to have a guilty conscience or to feel guilty. To feel you are to blame for something would be closer to "sich schuldig fühlen" and is indeed a more forceful expression.

FWIW "...have a bad conscience" sounds idiomatic to me.

I have often heard--and have said--"bad conscience." Of course, also "guilty conscience" and other variants.

I have a bad conscience about all sorts of things. The preposition is 'about', though, not 'for' or 'of' as in the ancient OP.

Certainly not "of." But I agree with those who think that "bad conscience for" is fine.

My first reaction before reading the new comments was that it's just a normal expression. Now that you mention it, 'guilty conscience' is probably more common, but I doubt that 'bad conscience' is wrong or Denglish. I don't think there's any significant difference in meaning.

I checked the modern AE text corpus and got 55 hits for 'bad conscience,' vs. 105 hits for 'guilty conscience.' That seemed reasonable to me.

http://corpus.byu.edu/coca/old/x3.asp?xx=1&w1...
http://corpus.byu.edu/coca/old/x3.asp?xx=1&w1...

*edit* I failed to notice the preposition, but I agree with escoville #13 that it should have been 'about.'

hm--us: