Short answer
A reliable way to find auto parts suppliers in Mexico is to start from public registries and narrow by process and size: INEGI’s DENUE lists 561 auto-parts plants with 11 or more staff across four Bajío states, and the IMMEX directory shows which hold export programs. Directories, associations and trade shows help after that.
Key facts
- Auto-parts plants, 11+ staff
- 561 in Aguascalientes, Guanajuato, Querétaro and San Luis Potosí (DENUE, 25 Sep 2026)
- With 51+ staff
- 486
- Median distance to the Laredo crossing
- 759 km straight-line for the 51+ set
Five sources, ranked by what they prove
| Source | What it gives you | What it cannot tell you |
|---|---|---|
| INEGI DENUE | Every registered establishment, with activity code, staff band and address | Export status, quality or tax standing |
| IMMEX directory | Which companies hold an export program, and its status | Plants under a shelter appear under the shelter’s name |
| SAT 69-B list | Names flagged under Article 69-B | Anything about a company that is not listed |
| Industry associations and state clusters | Member companies, introductions and events | Independent checks; membership is voluntary |
| Paid directories and sourcing agents | Search and introductions | It depends on how each one vets and who pays for placement |
The first three are public, free and published by Mexican authorities. Testigo reads all three for every plant it recommends. The last two are useful for introductions and market knowledge, and worth asking one question of: who pays for a company to appear?
The Bajío auto-parts base in numbers
| Process | Plants, 11+ staff | With 51+ staff | 51+ with an IMMEX match |
|---|---|---|---|
| Stamping and forging (336370, 332110) | 143 | 102 | 47 |
| Wire harnesses and electrical (336320) | 98 | 90 | 63 |
| Engine and powertrain (336310, 336350) | 95 | 78 | 52 |
| Seating and interior trim (336360) | 82 | 65 | 41 |
| Steering and suspension (336330) | 47 | 39 | 27 |
| Brake parts (336340) | 35 | 34 | 21 |
| Other auto parts (336390) | 109 | 102 | 73 |
Filters that turn a long list into five
- Process: map your part to an activity code (stamping, machining, harnesses, coating and so on).
- Size: staff band, from 11 or more to 251 or more, against the volume you need.
- State: the four Bajío states differ in mix; see the state pages.
- Distance: straight-line distance to your border crossing. Testigo measures to Laredo; road distance is longer.
- Registry checks: IMMEX status and the 69-B list, before anyone books a trip.
Frequently asked questions
How many auto parts plants are in Mexico’s Bajío?
INEGI’s DENUE lists 561 auto-parts plants with 11 or more staff across Aguascalientes, Guanajuato, Querétaro and San Luis Potosí, and 638 of all sizes. Of the 561, 486 have 51 or more staff. Testigo counted these from INEGI’s bulk files on 25 September 2026.
Which Bajío state has the most auto parts plants?
Among the four states Testigo counted, Guanajuato has the most in DENUE: 210 auto-parts plants with 11 or more staff, ahead of Querétaro (158), San Luis Potosí (107) and Aguascalientes (86). Other regions are outside Testigo’s pilot.
How do I know a Mexican auto parts supplier is real?
Confirm it in three public registries: DENUE for a registered establishment, the IMMEX directory for an export program, and the SAT 69-B list for tax-fraud flags. Then ask for its RFC and certificates, call references and visit. The registries narrow the list; they do not approve a supplier.