Cashed out an inherited Roth IRA from parent. box 2a on 1099-R is blank and box 2b is checked. box 4 is 0.00 and box 7 is T. Is the distribution taxable?

Code T means the administrator doesn't know whether the Roth IRA met the '5 year rule', but if you parents died in 2014 and you cashed out in 2019,  the rule has been met. 

(the rule is the income generated within the Roth IRA is taxable if the ACCOUNT hasn't been established for 5 years.  But on any day of the year you open the account, it's assumed it was opened on January 1.  So worst case, your parents opened this account on 1/1/14 so you meet the 5 year rule as of 1/1/19).  most probably, they opened the account before 2014, but it's a moot point now. 

The taxable distribution box should be set to zero and reported on your tax return.  There will be no impact on your return. 

Thanks so much!

Roth IRA beneficiaries can withdraw contributions tax-free at any time. ... Earnings from an inherited Roth can also be withdrawn tax-free, as long as the account had been open for at least five years at the time the account holder died.

If I understand both your reply as well as NCperson's reply correctly, then there appears to be a difference in opinion. NCperson seems to suggest that, because I waited up until the fifth year to make my withdrawal, then that certain 5-year rule, which concerns the length of time an account has existed, has been satisfied, and my withdrawal is tax-free. 

And your're saying that the account must have already been open for five years at the time of account owner's death. So if the account was opened in 2011, and the owner died in 2014, and I waited until 2019 to withdraw my entire inherited portion, then my withdrawal is taxable?

Just want to make sure I understand correctly before I start investigating when the original account was opened. Thanks!

NCperson's reply is correct.

LindaB1993's reply is a bit misleading in that it seems to imply that the 5-year holding period must be met prior to the death of the participant, but that is not true.  The distribution from an inherited Roth IRA is a qualified, nontaxable distribution if the distribution is made more than 5 years after the beginning of the year for which the decedent first made a Roth IRA contribution, which is obviously the case here even if that first contribution was made in 2014.

Contributions to an inherited Roth IRA can be withdrawn tax-free at any time.

As long as the account had been open for at least five years at the time the account holder's passing,  the earnings from the inherited Roth can also be withdrawn tax-free,

"As long as the account had been open for at least five years at the time the account holder's passing,  the earnings from the inherited Roth can also be withdrawn tax-free,"

JohnB5677, this is the same poorly worded statement as made by LindaB1993.  It can easily be misread to imply that earnings distributed at any time after death are only tax free if the participant had established the account 5 or more years before death.  That interpretation is a false statement.  If the participant made their first Roth IRA contribution in 2014 and later died that same year, distributions from the inherited IRA would be qualified distributions in 2019 and beyond, entirely tax free without regard to whether the distribution includes earnings.  Distributions prior to 2019 in this scenario would be taxable only upon dipping into earnings once all contribution and conversion basis was first distributed.

Another way to say this is that the 5-year clock for making distributions be qualified distributions does not freeze upon the death of the participant.