Since 2018, NOM-035-STPS-2018 has been applied in Mexico, focused on measuring psychosocial risk factors (PRFs) in workers and the Reference Guide III (RGIII) has been presented, however, research focused on its validation has been scarce, in very specific sectors and with small samples. Determine the levels of PRFs of five work centers and reliability and validity aspects of RGIII. The RGIII was applied to 1458 workers (806 women and 652 men) from five workplace in the industrial sector of Ensenada (Mexico), and the level of risk of the PRFs was analyzed, as well as their reliability and validity through Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA). The PRFs with medium, high and very high-risk levels are Workload, Lack of control over work and Workday. The RGIII presents adequate reliability with Cronbach's α, Alpha ordinal RHO and Omega of 0.93, 0.95 and 0.95, respectively. The EFA shows all five subscales maintain factor loadings greater than 0.43, although Leadership and relationships at work has better saturation values, and Work environment ended with only three items. The CFA indicates Leadership and work relationships with a Root Mean Square Error of Approximation (RMSEA) goodness of fit index of 0.072. The RGIII allows the identification and evaluation of the level of risk of PRFs. It complies with sufficient internal consistency. It does not have a clear factorial structure, because it does not meet the minimum values of goodness-of-fit indexes that would allow confirming the structure proposed in RGIII.