Limited research on chronic pain among Mexican Americans exists. Catastrophizing is a cognitive component of the experience of pain and has been measured using the Pain Catastrophizing Scale (PCS). However, only a Spain Spanish version of the PCS is available to be used with Spanish-speakers globally, which may not appropriate for Mexican Americans. The present thesis assessed the factor structure, internal consistency, and convergent validity of a new Spanish PCS among Mexican Americans. Participants were 182 Spanish-speaking Mexican Americans (56.6% female, 41.8% male, 0.1% gender queer; M age: 38.25 years, SD=9.41) who have chronic pain. Using a cross-sectional study design and convenience sampling, participants were recruited through Qualtrics Online Panels. Participants completed online surveys in Spanish assessing demographics, pain catastrophizing (PCS), depression (Patient Health Questionnaire-8; PHQ-8), anxiety (Generalized Anxiety Disorder-7; GAD-7), rumination (Ruminative Responses Scale; RRS- SF), fear of pain (Fear Avoidance Beliefs Questionnaire; FABQ), and perceived pain intensity and interference (PROMIS Pain Intensity and Pain Interference-SF). Confirmatory factor analyses (CFAs) were conducted to examine the factor structure of the new Spanish PCS. An initial CFA indicated good descriptive fit for a 3-factor model, but extremely high inter-factor correlations. A second CFA indicated good descriptive fit for a 1-factor model and significant factor loadings for all items. A Chi-Square Difference Test indicated no statistically significant differences between the two models, supporting a 1-factor model as a more practical and parsimonious fit. High internal consistency was established with Cronbach’s alpha (.95) and McDonald’s omega (.95) coefficients. The results of Pearson r correlational analyses indicated a strong correlation between scores on the PCS and the PHQ- 8 (r=.68), GAD-7 (r=.65), RRS-SF (r=.68 ), FABQ (r=.47), PROMIS Pain Intensity-SF (r=.63), and Pain Interference-SF Scales (r=.72; all ps<.001), providing evidence of convergent validity. As a single-factor model, the new Spanish PCS is an appropriate measure of pain catastrophizing. However, this sample did not seem to perceive items as measuring distinct components of catastrophizing. These results suggest caution when using subscale scores as indicators of constructs that may vary across ethnic groups and highlight the importance of cultural and linguistic competency in measures among different Hispanic subgroups.