Hippostratus was an Indo-Greek king who ruled central and north-western Punjab and Pushkalavati. Bopearachchi dates Hippostratos to 65 to 55 BCE whereas R.C. Senior suggests 60 to 50 BCE.
In Bopearachchi's reconstruction Hippostratus came to power as the successor to Apollodotus II, in the western part of his kingdom, while the weak Dionysius ascended to the throne in the eastern part. Senior assumes that the reigns of Apollodotus II and Hippostratus overlapped somewhat; in that case Hippostratos first ruled a kingdom was to the west of Apollodotus dominions.
Just like Apollodotus II, Hippostratus calls himself Soter, "Saviour", on all his coins, and on some coins he also assumes the title Basileos Megas, "Great King", which he inherited from Apollodotus II. This may support Senior's scenario that Hippostratus extended his kingdom after Apollodotus' death. The relationship between these two kings remains uncertain due to lack of sources. Hippostratus did however not use the symbol of standing Athena Alkidemos, which was common to all other kings thought to be related to Apollodotus II. The two kings share only one monogram.
 The quantity and quality of the coinage of Hippostratus indicate a quite powerful king. Hippostratus seems to have fought rather successfully against the Indo-Scythian invaders, led by the Scythian king Azes I, but was ultimately defeated and became the last western Indo-Greek king.
Azes I (57-35 BCE) was an Indo-Scythian ruler who completed the domination of the Scythians in northern India.
Although Maues and his successors had conquered the areas of Gandhara, as well as the area of Mathura from 85 BCE, they were unsuccessful against the Indo-Greek kings remaining behind the Jhelum River in eastern Punjab.
The Indo-Greek Hippostratos (65-55 BCE) finally lost to Azes I after a long resistance. Some coins of Azes I depict the god Poseidon vanquishing a horned river god, suggesting a naval victory over a river, probably the Jhelum
. The final battle probably took place near Taxila, the capital of the western Indo-Greeks. 
The Indo-Greeks continued to maintain themselves in the eastern Punjab for several decades, until the kingdom of the last Indo-Greek king Strato II was taken over by the Indo-Scythian ruler Rajuvula  around 10 CE. The coins of these Indo-Greek rulers deteriorated constantly, both in terms of artistic quality (due to the long isolation) and in silver content. Still, the last Strato had the honour of ruling the last pocket of an independent Hellenistic state; when he disappeared, Cleopatra, usually seen as the last of the rulers who followed Alexander the Great, was already gone
