My net rental income on Federal return (schedule E) is a loss. But one property in Ohio is a net $300 gain $300. Do I need to file in Ohio if I live in NY?

NY will give you credit for any tax paid to OH; prepare the OH return first.  Your rental income on Schedule E will be transferred to the Ohio return.  Ohio begins with federal AGI.   Additions and deductions are computed as adjustments on Ohio Schedule A. Personal and dependent exemptions are then subtracted to arrive at Ohio income tax base.   For part-year residents and nonresidents, Ohio tax is computed on total income.  The tax is then multiplied by a percentage based on non-Ohio income compared to Ohio AGI.   Everything but the OH rental is non-Ohio income.  

You do not have to file an Ohio income tax return if ...

• Your Ohio adjusted gross income (line 3) is less than or equal to $0.
• The total of your senior citizen credit, lump sum distribution credit and joint filing credit (Ohio Schedule of Credits, lines 4, 5 and 12) is equal to or exceeds your income tax liability (Ohio IT 1040, line 8c) and you are not liable for school district income tax.
• Your exemption amount (Ohio IT 1040, line 4) is the same as or more than your Ohio adjusted gross income (line 3) and you have no amounts on your Schedule of Adjustments.

However, even if you meet one of these exceptions, if you have a school district income tax liability (SD 100, line 2), you are required to file the Ohio IT 1040.

NOTE: If your federal adjusted gross income is greater than $28,450, the Department of Taxation recommends that you file an Ohio IT 1040 or IT 10, even if you do not owe any tax, to avoid delinquency billings.

OHIO IT 10: Certain taxpayers can file the Ohio form IT 10 instead of the Ohio IT 1040. The four types of taxpayers described on the form are eligible to file if they:

• Do not have an Ohio individual income or school district income tax liability for the tax year; AND
• Are not requesting a refund.