© 2019 Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd. The production of Ξcc++ baryons in proton-proton collisions at a centre-of-mass energy of √s = 13TeV is measured in the transverse-momentum range 4 < PT < 15 GeV/c and the rapidity range 2.0 < y < 4.5. The data used in this measurement correspond to an integrated luminosity of 1.7 fb-1, recorded by the LHCb experiment during 2016. The ratio of the Ξcc++ production cross-section times the branching fraction of the Ξcc++ → Λc+ K-π+ π+ decay relative to the prompt Λc+ production cross-section is found to be (2.22 ± 0.27 ± 0.29) × 10-4, assuming the central value of the measured Ξcc++ lifetime, where the first uncertainty is statistical and the second systematic.