From 130 BC a nomadic people, the Yuezhi, started to invade Bactria from the north and we could assume that Heliocles was likely killed in battle during this invasion. Details from Chinese sources seem to indicate that the nomad invasion did not end civilisation in Bactria entirely. Hellenised cities continued to exist for some time, and the well-organised agricultural systems were not demolished.
The Yuezhi would copy and adapt the coin types of Heliocles I for a long time after the latter's death.
Heliocles I used the Greek epithet Dikaios ("the Just") on his coins. There is evidence that Heliocles I ruled around the same time as Eucratides II, as a silver coin has been discovered showing both rulers sharing the coin in a joint issue.