Italy faced Sweden in a two-legged World Cup qualification play-off and ultimately fell short of expectations, losing 1-0 on aggregate thanks to the first-leg defeat in Solna.
The four-time world champions will miss the tournament for the first time since 1958.
Ventura was under pressure even before the 0-0 draw at San Siro on Monday confirmed their absence from Russia next year, with failure effectively ending his tenure.
