A nonexempt employee (i.e. one who can receive overtime; all hourly staff) must be paid for all hours worked, and must get overtime if he or she works more than 40 hours in a week. Furtheremore, the employer must keep honest and accurate time records. So it appears that your employer has violated the law and potentially given you a claim or cause of action. However, as a practical matter, if this only happened once or twice, there really is nothing to about it--the amount you could recover is far less than the cost of a lawsuit, and it's unlikely that the labor department would be concerned or interested enough to intervene. If it's happened often, speak to an employment attorney; otherwise, keep careful records to see if the violations mount up to a worthwhile leve. Good luck.