Assuming the child qualifies as your dependent by meeting the five tests, claiming a child gives you a deduction of $3800 (for 2012) off your taxable income as does every person on the return. But with a child that meets the requirement as YOUR child you also may qualify for various filing statuses and credits, like head of household versus single filing status with its higher standard deduction and lower tax tables, child tax credit if the child is under 17, child care credit if the child is under 13, and earned income credit and/or education credits if the child is under 19 (or 24 if a student).