OBJECTIVES: This study investigated the effect of body mass index (BMI) and related comorbidities on quality of life, work productivity, activity impairment, healthcare resource utilization, and associated costs in Mexico.   METHODS: Data were collected using a cross-sectional survey of adults in Mexico (N=2,511) identified from a combination of Internet panels and offline recruitment.  Recruitment was made to ensure the demographic composition of the sample mimicked the total adult population. The analysis focused on respondents with normal weight (BMI≥18.5 & <25 kg/m), overweight (BMI≥25 & <30 kg/m), obesity class I (BMI≥30 & <35 kg/m), class II (BMI≥35 & <40 kg/m), or class III (BMI≥40 kg/m). Demographics, comorbidities (e.g., hypertension, dysglycaemia), health outcomes such as quality of life (EQ-5D), work productivity and activity impairment (WPAI questionnaire), healthcare resource utilization, and indirect costs were assessed.  Generalized linear models were used to test the association between BMI levels and health outcomes, controlling for covariates (e.g., age, sex, comorbidities). RESULTS: The sample was 50.6% male with a mean age of 40.7 years (SD=14.5); 38.3% were overweight and 24.4% reported a BMI≥30.  75.2% of individuals with BMI ≥35 had dysglycaemia (29.9% type 2 diabetes mellitus (T2DM) and 45.3% pre-diabetes). Increasing BMI was associated with significant impairment in quality of life (health utilities ranging from 0.84 for normal weight, down to 0.76 for people with BMI≥35). Increasing BMI was also associated with greater overall work impairment (from 18.8% up to 25.8%), activity impairment (from 15.8% up to 24.8%), and indirect costs (from 35122 MXN up to 48090 MXNs). A similar pattern of results was found in the T2DM, pre-diabetes, and hypertension subgroups. CONCLUSIONS: Results suggest a significant effect of increasing BMI and comorbidities on quality of life and work productivity.  Improvement in the management of the obesity epidemic could have significant benefits to the patient and society.