Another thing to consider is, if the misdemeanor was associated with an actual arrest then FBI records will tell them when where and why, and you had better tell them first. The expunged part might stay a secret otherwise, a lesson learned in the distant past, but the arrest may bring it out anyway. If you are sure there is no arrest record and the other sources mentioned above are clear, it remains a gamble whether or not to disclose it. Honesty is the best policy in general, but bear in mind some companies are not asking because they are so ethical and moral it's legal and liability reasons, so if you are not bound not tell by way of an expunging, then they themselves would rather that you not tell about it. On the other hand, if you have dependents and really can't afford to gamble with their future I would go the disclosure route and hope you still get the job.