My mother passed September 2017- she has been paying estimated tax and made a payment in August 2017 just before she passed. Do I need to file income tax?

[Critter]

Yes ... someone must file a final return for the decedent. https://www.irs.gov/businesses/small-businesses-self-employed/deceased-taxpayers-probate-filing-esta...

[VolvoGirl]

Yes if she was paying estimates then she must have income to report.  Like self employment income or investments.  Get a copy of her 2016 return and try to find her paperwork and tax forms you can use to follow for 2017 so you don't miss anything.  Be on the look out for her 1099s, etc. to come in the mail in January.  

How old was she?  Was she getting Social Security or pension? Did she use Turbo Tax?