Prodigy's official cause of death is listed as accidental choking ... TMZ has learned.

The Clark County Medical Examiner has made the determination after completing its investigation into Prodigy's June 20 death. As TMZ first reported, he was in a Las Vegas hospital when he choked on an egg.

Prodigy was in the hospital getting treatment for sickle cell anemia -- which he'd battled his entire life, and had flared up immediately following a performance in severe Las Vegas heat.

The Mobb Deep MC was 42.

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