Possible if there were extenuating circumstances, like medical, divorce ect however 600 is the preferred score. Mark Roos of Wells Fargo can give you some tips to buid your score,

Yes, you can. The problem is that most FHA lenders have increased their minimum scores to 620 - but there are a few left that will underwrite files with middle scores down to 530. Please realize that there needs to be a really good reason that your scores are suffering in order for an underwriter to validate your credit history and qualify you for an FHA mortgage with a 575. It will not be easy.

As for boosting scores - there are probably several reasons that your scores are down - the main things that I see on credit bureaus with sub-600 borrowers are:
1. Revolving credit balances that are over half of the cards' limit. If you have a Sears card with a limit of $1000 and a balance of $800 you aren't doing yourself any favors - it would be much better if you carried a balance at $300 or below.
2. Collections or judgments are typical to drag a score down. If there is inaccurate information on your report, you can take the time to get things fixed or you can even pay a professional to make these thing happen if you do not feel that you can take the time to do it yourself.

Hope this helps!