I am doing my 2018 tax returns and have a question about 1099-G and amended tax returns. I received 1099-G in January 2019 for tax year of 2017 (for state income tax refund). After receiving my 1099-G, in Feb 2019, I realized that I made a mistake in my 2017 tax return and filed an amended return. As a result, I repaid back most of my state refund. Now that I am preparing my 2018 tax returns I understand that I can report the additional state income tax I paid with the amended return on the deductions and credits page under "estimates and other income taxes paid." My question is that since I paid that additional state income tax in 2019 (not in 2018) can I still report it in my 2018 tax returns or I should report it next year in my 2019 tax returns? I emphasize that the additional state income tax that I paid was because of amended 2017 tax returns.