Developmental theories suggest age-related changes in the structure of affect. Paradoxically, the internal structure of the Positive and Negative Affect Schedule (PANAS; Watson, Clark, & Tellegen, 1988) has not been tested in Spanish older adults by means of confirmatory factor analysis (CFA) despite it is the most widely used measure of emotional well-being in later life. The aim of this study was to examine competing models of the internal structure of the Spanish version of the PANAS, its measurement invariance, reliability, and external validity. Participants were a representative sample of 585 community-dwelling people aged 60 and over, who also completed depression, loneliness and life satisfaction measures. Results showed that the orthogonal two-factor model with correlated errors (RMSEA = .057, 90% CI [.051, .063], SRMR = .084, CFI = .97, NNFI = .97) was the best fitting solution. Measurement invariance analyses confirmed that the two-independent factor structure can be used across young-old and very old people, as well as in both males and females. It showed good reliability (PA: α = .93, NA: α = .83), criterion, convergent and discriminant validity (p < .01). Our discussion highlights the role of age and culture in the experience and expression of emotions.