Mexico is considered one of the most important global producers of motor vehicle. It has the 7^th place as a worldwide producer with a contribution of 3.8% of total production. Nuevo Leon is one of the most important states of the country, with a high performance in automotive industry. This is because it has automotive parts suppliers with a continuous growth in their exports and production despite the adverse political situation with the NAFTA. The present research finds factors with high relevance for the manufacturing competitiveness of the automotive parts suppliers in the automotive industry of the state of Nuevo Leon, Mexico. These findings are supported by an exhaustive literature review. This research defines also a competitiveness measurement instrument, which is composed of two content tests with academics experts and operational directors of automotive parts suppliers. The results obtained show the level of relevance and concordance of each item of the factors of product and process quality, product innovation and process technologies.  This study presents an analysis of the content of the measurement instrument for each of the factors, and how they impact the manufacturing competitiveness of the automotive industry parts suppliers in Mexico.