I Have to Have a Background Check for a Job!?

Its for a administrative assistant position in a drug rehab facility. 5 years ago I have a theft (mistemeanor) charge on my record from a different state. Will this stop me from getting the job, or will they be looking for just felonies, sex offenders, etc..? Also do they do the checks before they make the decision of hiring you?? I have my second interview today, and its between me and 2 other people.. SO before they pick, will they do the checks???