True. See IRS Pub 590-B regarding the ordering rules for distributions from Roth IRAs:
https://www.irs.gov/pub/irs-pdf/p590b.pdf
macuser_22 describes the reporting on Form 8606 required to determine the taxable amount of any Roth IRA distribution that is not a qualified distribution.
Be aware the that rules for distributions from a Roth account in a qualified retirement plan (401(k), 403(b), 457(b) or the federal TSP) follow different rules because they are not Roth IRAs. Distributions from Roth accounts in qualified retirement plans are are instead proportionate mix of contributions and earnings.
