T The purpose of this study was to determine the content of limestonenanofossils in LN wells in the North East Java basin. As for the purpose of thisstudy to know the biostatigraphy of the samples studied in the study area. A totalof 73 rock samples in the form of drill cuttings originating from a well depth of25-1465m were analyzed quantitatively to determine the lithology and content ofcalcareous nanofossils using the smear slide method. From lithologicalobservations, it is known that there are 2 rock units, namely Shale-insertedClaystone units and Sandstone-inserted Shale units which are comparable to theTawun Formation and the Ngrayong Formation. From the observations, 15058specimens were identified consisting of 11 genera and 26 species and 6 datums,namely Helicosphaera ampliperta, Sphenolitus heteromorphus, Cyclicargolithusfloridanus, Discoaster hamatus and Catinaster coalitus. Based on this datum,zoning was successfully arranged based on Martini (1971), which found in LNwells, namely Zone NN4, Zone NN5, Zone NN6, Zone NN7, Zone NN9 and ZoneNN10 or early Miocene to late Miocene. Furthermore, based on the datum crossplot, it is known that the sedimentation rate consists of 16.7cm/kyr at a depth of440-445m, 17cm/kyr at a depth of 520-522m, 58cm/kyr at a depth of 540-542m,21cm/kyr at a depth of 820-822m, 12cm/kyr at a depth of 860-862m. from theresults of the study it was known that there was an unconformity at a depth of540m, where 2 biodatums were found, namely Discoaster hamatus and Catinastercoalitus present together