Health inequities exist in groups of greater psychosocial vulnerability such as emerging adults and migrants. The study aimed to generate evidence of the validity of the mental and physical health symptomatology scale in two samples of vulnerable groups: emerging university adults, who report high levels of mental health problems, and migrants, who report high levels of physical and mental health problems. Using non-probability sampling, in the first study, evidence of construct validity of the scale was reported in 652 emerging adults and, in the second, evidence of validity was provided from associations with the depression, stress and anxiety scale (DASS-21) among 283 migrants. The results indicate that in Study 1 the two-factor model had adequate indicators of fit and adequate reliability; only the mental health factor presented evidence of convergent validity. In Study 2, the mental health factor showed positive and large associations with the DASS-21, which decreased when the physical health symptoms factor was considered. These analyses provide evidence of validity for the scale, which is an easy-to-use instrument that allows for the assessment of health from an integral perspective.