Can someone withdraw money from my account if they have my account number and routing number?

Do you mean a person or an institution?

Institutions use that info in order to transfer funds electronically from your account.

As for an individual, they wouldn't just be able to take that info to a bank and pull out money. They would need a check from you saying that you are authorizing a specific amount of money to be given to them.

However, you do want to protect this info from getting into the wrong hands by not leaving your account info laying around that it may be stolen.

They could potentially purchase something from the internet that allows them to use a bank account. I've seen many sites where you need the account & routing number and bank name. If you are worried, go to your bank and let them know what's going on so they can help protect your account.

Of course anyone you write a check to has those numbers since they are printed on every check you write.

Is it possible, yes ( electric funds transfers) Same way you do electric banking, automatic depoists, automatic payment of bills.

It would probably be a good idea to contact your bank immediately and let them know what's going on. Yes they probably could access your account by walking into your bank, unless your bank requires picture ID. I know with my bank I don't have to show picture Id, I just have to give them my account number. Keep a close eye on all transactions because if someone does access your acct then you'll be responsible for it, unless you can prove otherwise. Good luck

Why do you ask?

Everyone you give a check to has you name, routing # and account #. The information is useless unless it is comprised in conjunction with additional identity theft such as social security, driver license. etc.