The acquisition includes three natural gas pipelines, an ethane pipeline, a liquid petroleum gas (LPG) pipeline and a LPG storage terminal.
With this acquisition, IEnova will become the sole owner of the Gasoductos de Chihuahua project.
Sempra Energy president Mark Snell said: "This acquisition creates incremental value for IEnova and Sempra Energy shareholders by expanding our asset base and operating capabilities in Mexico.
"It provides opportunities to leverage our resources and grow in the marketplace."
Under the deal, IEnova and Pemex will maintain a joint venture for the Los Ramones Norte pipeline project, which transports natural gas from US to Mexico.
Subject to regulatory approvals and other customary closing conditions, the transaction is planned to be completed within four months.
