Emodiversity, or the variety and relative abundance of emotions experienced, provides a metric that can be used to understand emotional experience and its relation to well-being above and beyond average levels of positive and negative affect. Past research has found that more diverse emotional experiences, both positive and negative, are related to better mental and physical health outcomes. The present research aimed to test the relationship between positive and negative emodiversity across the span of 8 days with measures of health and well-being using 2 samples of the Midlife in the United States study (http://midus.wisc.edu/). Participants (N = 2,788) reported emotional states (14 negative, 13 positive) once each day for 8 days. Emodiversity scores were computed for each day using an adaptation of Shannon's biodiversity index and averaged across the days. All models included average affect and demographic covariates. Greater positive emodiversity was associated with fewer symptoms of depression and anxiety and fewer physical health symptoms but was not related to eudaimonic well-being nor cognitive functioning. In contrast to previous research, greater negative emodiversity was related to more symptoms of depression and anxiety and more physical health symptoms. Greater negative emodiversity was only associated with one positive outcome: better executive functioning. These findings illustrate inconsistencies across studies in whether negative emodiversity is associated with better or worse outcomes and raise further questions about how the construct of emodiversity can be better refined. (PsycInfo Database Record (c) 2022 APA, all rights reserved).