The joint venture plans to develop 1GW of renewable projects in Mexico by 2020. The Mexican government has set a target to produce 35% of its energy from renewables by 2024.
Pattern Energy CEO, Mike Garland, said a move in to Mexico was a "natural expansion".
Pattern's renewable energy division retains a right of first offer for projects developed by its parent company, which formed the JV with Cemex Energia.
Cemex is a building materials company based in Mexico and the US with a global customer base. Its renewables division jointly developed the 250MW Eurus cluster in Oaxaca, southern Mexico, with Acciona.
Pattern Energy owns 1.6GW of wind power in the US across 12 projects.