"It has been identified that sarin gas was used," Turkish Health Minister Recep Akdag said, quoted by state-run news agency Anadolu.
The results came from analysis of blood and urine samples of the casualties from the attack in Idlib province who were brought to Turkey for treatment. Three of them died in hospital.
The incident which killed 87 civilians, including 31 children in the rebel-held town of Khan Sheikhun has been blamed on Syrian President Bashar al-Assad's regime by Turkey and the United States.
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Akdag said isopropyl methylphosphonic acid was found, which is what results after sarin is exposed to the environment.
Sarin can be inhaled or absorbed through the skin and kills by crippling the respiratory centre of the central nervous system and paralysing the muscles around the lungs.
Images from the town where the attack took place showed victims suffering convulsions, breathing problems and foaming at the mouth.
Days after the incident, the US blasted 59 Tomahawk missiles at the Shayrat air base near Homs which Washington believes Assad's jets launched the attack from.
Turkish Foreign Minister Mevlut Cavusoglu earlier in the day said the regime still had "chemical weapons capacity" as top diplomats gathered for G7 talks in Italy.