A measurement of time-dependent CP violation in D-0 -> pi(+) pi(-) pi(0) decays using a pp collision data sample collected by the LHCb experiment in 2012 and from 2015 to 2018, corresponding to an integrated luminosity of 7.7 fb(-1), is presented. The initial flavor of each D-0 candidate is determined from the charge of the pion produced in the D*(2010)(+) -> D-0 pi(+) decay. The decay D-0 -> K- pi(+) pi(0) is used as a control channel to validate the measurement procedure. The gradient of the time-dependent CP asymmetry Delta Y in D-0 -> pi(+) pi(-) pi(0) decays is measured to be Delta Y = (-1.3 +/- 6.3 +/- 2.4) x 10(-4), where the first uncertainty is statistical and the second is systematic, which is compatible with CP conservation.