Rachid Idrissi died on October 18, 1971, in Salé in a car accident after being hit by a truck on National Road 15 while crossing a bridge on Bou Regreg from Rabat on his way to his hometown of Outat El Haj. His sudden death immediately raised suspicion of a political assassination from his entourage. He was buried in the cemetery in Douar El Kchahda, near Outat El Haj.
During a speech at his funeral, engineer Mohamed Ait Kaddour, a colleague of Idrissi, stated that he fell victim to "his involvement in establishing a defense project in the Arab world based on his possession of science, knowledge, and ability". A scholar in Idrissis hometown, Hajj Mohamed Harmouche, blamed his death on "external parties". Newspaper Al Ittihad Al Ichtiraki' claimed that Idrissi had been surveilled by foreign intelligence agencies prior to his death, but this remains unconfirmed.
A posthumous Rachid Idrissi El Ouatati Prize for Criticism was created in May 2023 by the Oboure Cultural Publishing Association in Rabat, the prize crowns works of literary criticism in Morocco and commemorates Idrissi. In December 2023, a synopsium was held by the Moulay Rachid Idrissi Center for Studies and Research in Outat El Haj regarding Idrissi's life.