What AM said is correct.........  frequently, if you have a NJ resident who works in NY the W2 will not tell you the NJ taxable wages but they'll list the Cafe 125, 403b, etc on the W2. You have to know those items are NJ taxable. On the NJ1040 in PS there's a worksheet under line 14 where you can add back the NJ taxable items to the return.