In the presented work, there is studied the issue of the Roman border defense system in the Eastern Black Sea region on the base of an analysis of antique sources; It is shown that this system was part of Rome's common- eastern frontier-defense line. The Eastern part of Black Sea coast, historical Colchis, as a secure rear and strategic beachhead against Parthia in the battle for Armenia, had a well-defined place in the Roman geopolitics. Besides, Colchis had a great communicative significance relative Bosporus. Of course, the political situation in East had a big influence on relations of this region with Rome.In 63 A.D., after the abolition of the Kingdom of Pontus by Nero (54-68), Colchis was occupied by Romans and it became the part of the province of Galatia. By the order of Nero, Roman garrisons were stationed in the seaside settlements of Colchis – Apsarus, Phasis and Sebastopolis. These measures were the starting point of establishment of the Roman frontier-defence system in the Eastern Black Sea coast. This system began its actively functioning in Vespasian’s time. During the rule of Vespasian (69-79) Colchis was the part of united Cappadocia-Galatia, so called “Cappadocian complex”. Bording the Euphrates river to the east, Cappadocia was the most eastern province of the Empire. The military presence in Cappadocia served as an important response force against invasions from the Parthian Empire and allowed the Roman's easy intervention into the affairs of their client kingdom of Armenia. The ,,Cappadocian Complex” received two legions. These legions were located on the Cappadocia-Lesser Armenia line, in Satala and Melitene. In the I-III centuries the Roman garrisons of the coastal fortresses of Colchis were subordinate to the Asia Minor forces of the empire; the main command of these forces was located in the Cappadocia. Later garrisons began to obey the Armenian duke.Of all the fortresses of the Eastern Black sea coast, Apsaros is the closest to the immediate borders of the Roman Empire. For a long time Apsaros was one of the significant points of the Pontus-Caucasian border line, the Roman frontier defensive system at the coast of the East Black Sea. The mentioned defense system, as you know, was founded in the times of emperor Nero's reign (54-68 A.D.), the 60's of the 1-st century. The first Roman garrison appeared in Apsaros at that very time. In the 2-nd century five cohorts were dislocated in Apsaros. At the time of the visit to Apsarus by Flavius Arrian (131 A.D.), there was a powerful garrison, numbering from a thousand to two and a half thousand soldiers. As for other Roman fortresses of the Eastern Black Sea region, on the base of an analysis of antique sources, it turns out that during Nero (54-68) roman garrisons were dislocated in Fasis. For the first time, the Roman fortress in Fasis mentions Flavius Arrian (nearly 95-175), who left us a very detailed description of it. In the 2nd century 400 soldiers were dislocated in Fasis; The first Roman garrison, for a short period, appeared in Sebastopolis In the era of Augustus (27 B.C.-14 A.D.). According to archaeological and antique written sources, In the 2nd-3rd centuries the garrison of Sebastopol consisted of 200-300 soldiers. The basic purposes of the Pontus Caucasian frontier-defence system were consolidation of the Roman power in the region, taking control of the passages to the Northern Caucasus, and protection of coastwise navigation. In the middle of the II century, after inclusion of Pityus into this system, formation of the Pontus Caucasian frontier-defence line was finished.