74,865,585 - but I could be wrong.

A legion contains bout 50,000,000 soldiers

6,000 http://en.wikipedia.org/wiki/Roman_army

The size of a typical legion varied widely throughout the history of ancient Rome, with complements of 4,200 legionaries and 300 equites in the republican period of Rome, (the infantry were split into 35 maniples of 120 legionaries each), to 5,200 men plus auxiliaries in the imperial period (split into 10 cohorts, 9 of 480 men each, plus the first cohort holding 800 men). The full legion number was supposed to be 6 000, but was rarely achieved.

Draftees or enlisted? - BTW: The dude who answered ~74 million must be counting civilian ancillary personnel. ;-)

1) "The Roman Legion (from Latin legio "military levy, conscription", from legere — "to choose") is a term that can apply both as a transliteration of legio ("conscription" or "army") to the entire Roman army and also, more narrowly (and more commonly), to the heavy infantry that was the basic military unit of the ancient Roman army in the period of the late Roman Republic and the Roman Empire. In this latter meaning, it consisted of several cohorts of heavy infantry known as legionaries. It was almost always accompanied by one or more attached units of auxiliaries, who were not Roman citizens and provided cavalry, ranged troops and skirmishers to complement the legion's heavy infantry. The size of a typical legion varied widely throughout the history of ancient Rome, with complements of 4,200 legionaries and 300 equites in the republican period of Rome, (the infantry were split into 35 maniples of 120 legionaries each), to 5,200 men plus auxiliaries in the imperial period (split into 10 cohorts, 9 of 480 men each, plus the first cohort holding 800 men). As legions were not standing armies until the Marian reforms (c. 107 BC), and were instead created, used, and disbanded again, several hundred legions were named and numbered throughout Roman history. To date, about 50 have been identified. In the time of the Early Roman Empire, there were usually about 25-35 standing legions plus their Auxiliaries, with more raised as needed. See List of Roman legions for a catalogue of known late republic, early Empire and late Empire legions, with dates in existence, emblem and locations of deployment. Due to the enormous military successes of the Roman Republic and the Roman Empire the legion has long been regarded as the prime ancient model for military efficiency and ability." Source and further information: http://en.wikipedia.org/wiki/Roman_legion 2) "Legio I Germanica Active 48 BC to 70 Country Roman Republic and Roman Empire Type Roman legion (Marian) Role Infantry assault (some cavalry support) Size Varied over unit lifetime. Approx. 3,500 fighting men + support at the time of creation." Source and further information: http://en.wikipedia.org/wiki/Legio_I_Germanica "Legio II Parthica Active 197 to sometime in the 5th century Country Roman Empire Type Roman legion (Marian) Role Infantry assault (some cavalry support) Size Varied over unit lifetime. Approx. 5,500 fighting men + support at the time of creation." Source and further information: http://en.wikipedia.org/wiki/Legio_II_Parthica