My employer is not paying me for all my hours and asking me to claim cash shortages. Is this legal?

If you are not an exempt employee, that is, you don’t meet the requirements to be an exempt executive (manager), learned professional, creative professional, computer professional, or administrative employee—then yes, the employer must pay you for all hours worked. If you are working the register as a cashier, then you are almost certainly not exempt, and in that case, not only must you be paid for all hours worked, but you should also earn overtime (time-and-a-half) for all hours worked beyond 40 in a workweek. Failure to pay a nonexempt employee for all hours worked can result in an employer being liable for all back wages it should have paid, for a start; if you think that you haven’t been paid for all your hours, you should speak with an employment lawyer.

As for forcing you to make up shortages from the cash drawer: If it was a known and agreed to term of your employment that you would have to make up shortages or missing amounts, then in theory the employer may make you pay this amount. That said, to prevent abuses, most states put very strict limitations on whether and how an employer can do this. If it was a known and agreed-upon condition of your job, you may have to make the amount up, and you might consult with an employment attorney in your state to be sure. There is a good chance that the employer’s actions will not pass muster, but if the policy was something you knew about and agreed to (even if only implicitly, by continuing to work there), there’s at least the chance this is legitimate.

If an employer legitimately believes you stole from it, it has a number of other options. It could fire you, for a start. It could report you to the police for theft. It could sue you for the amount, the same way it could sue anyone it believed stole from it. Therefore, even if the employer couldn’t, for example, debit money from your paycheck, there are still consequences. The short answer is, if you are taking money, don’t—it subjects you to civil and criminal liability. If you’re not but your employer is accusing you of doing so, then think about whether you want to work with or for someone who might wrongly report you to the police or threaten to sue you.