Yes you can if the child lived with you. Answer the interview that the child is your child (not you and your present spouse if filing jointly), YES - you have a custody agreement, and YES - the other parent is claiming this year.
Your child will NOT be your dependent - he will be a non-dependent for EIC, Dependent Care & HOH only.
This is the special rule for Children of divorced or separated parents (or parents who live apart)
http://www.irs.gov/publications/p17/ch03.html#en_US_2013_publink1000170876
The absent parent can claim the dependent (child's exemption) and Child Tax credit.
You can see all the rules for HOH at this IRS link:
http://www.irs.gov/publications/p17/ch02.html#en_US_2013_publink1000170792
You might consider amending your 2011 tax return if it increases your refund.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
