Based on cyclostratigraphy and sequence stratigraphy criteria, an orbital chronostratigraphy is here proposed for the Upper Valanginian/Lower Hauterivian (Lower Cretaceous) stratigraphic interval. For such a purpose two biostratigraphically constrained carbonate platform sections have been measured and sampled at centimetre scale in southern Italy: (1) San Lorenzello, Matese Mountains in Campania Apennines, and (2) Sferracavallo, Palermo Mountains in north-western Sicily. The former has a thickness of about 87 m while the latter totals about 40 m. Analysis of depositional and early diagenetic features has shown that both the successions are characterized by internal cyclicity, consistent with orbital (Milankovitch) forcing. This high-frequency cyclicity, in which the elementary cycles are organized in bundles and in groups of bundles (superbundles), appears to be superimposed on three longer (from about 800 ky to about 1200 ky) Transgressive/Regressive Facies Trends (T/RFTs). While the elementary cycles record the precession and/or the obliquity signal (or a combination of them), the bundles and the superbundles correspond to the short- and long - eccentricity signals (about 100-ky and 400-ky cycles) respectively. Sequence stratigraphy criteria, used to interpret the superbundles and the T/RFTs in terms of depositional sequence-equivalents, allowed us to propose chronostratigraphic diagrams of the studied intervals and to attempt regional- to global-scale physical correlations. At regional scale, the Sferracavallo section was correlated, bundle - by - bundle, with the time-correspondent segment of the San Lorenzello section. The chronostratigraphic correlation shows that only one main gap, calculated in about 200 ky, occurs in the studied intervals. This allows us to estimate that the sedimentary record may be considered quasi-continuous, at least at the superbundle scale (about 400 ky). The assembled orbital chronostratigraphy suggests that the time recorded in the San Lorenzello and in the Sferracavallo sections is of 2.9 and 1.9 my, respectively. At global scale, a physical correlation is proposed with the time-equivalent 3rd order sequences of Haq et al. (1987) and Jacquin et al. (1998), taking into account the stratigraphic position of the Valanginian/Hauterivian (Early Cretaceous) boundary in the standard time scales, as well as in our orbital chronostratigraphy. This correlation shows that there is a good agreement between the 2.6-my time duration of the stratigraphic interval spanning from the Valanginian 4 to the Hauterivian 1 sequence boundaries (Jacquin et al., 1998) and the 2.8-my time interval estimated on the basis of our orbital chronostratigraphy.