Hi Glohgloh!
Yes, if you have dependents that you can claim, they can be added to your tax return by filing an amended tax return on Form 1040X. Don't forget to amend your state return also if you were required to file a state return. Before filing, you will need to make sure not only are you eligible to claim the dependent, but also that they have not been claimed by someone else or reflected on their return that they could not be claimed by someone else. If they have been claimed by someone else or showed that they could not be claimed by someone, they would need to amend their return(s) prior to your claiming them.
