Josephus has supplied us with a detailed description of Alexander Jannaeus' defensive alignment, erected in ca 86/85 B.C.E. against Antiochus XII Dionysus on his way to Arabia. The term 'Yannai Line' was coined by the late J. Kaplan, who in a series of preliminary publications attempted to relate archaeological remains discovered in Tel Aviv and Bene Braq to this defensive alignment. Archaeological and historical studies dealing with the Late Hellenistic (Hasmonean) period in Ancient Israel have often mentioned these remains to illustrate historical validity in archaeological reality. This article analyses the finds from Kaplan's excavations (which were never fully published) and examines Kaplan's interpretation of the remains. We conclude that Kaplan's interpretation of the excavated remains as belonging to a Jannaeus' defensive line is misleading, and thus one can not refer to the 'Yannai Line' as identified by Kaplan. We also raise doubts to the authenticity of the historical sources and tend to dismiss Josephus' statement (copied from Nicolaus of Damascus) about the 'Yannai Line' in the form it is described. We therefore suggest that at the present state if research the term 'Yannai Line' should be excluded from future scholarly works.