Daily associations between affect, drinking motives, and drinking intensity among U.S. young adults.Objective: We investigated the relationships between daily affect, drinking motives, likelihood of drinking, and intensity of drinking, particularly high-intensity drinking (HID), in a sample of young adults. We also explored differences in our outcomes before versus during the early coronavirus disease (COVID-19) pandemic. Method: In the springs of 2019 and 2020, young adult drinkers (N = 633) completed 14 consecutive morning surveys (each year) characterizing the prior day’s affect, motives, and alcohol use. We examined between-person and within-person associations of affect and motives with two outcomes: any drinking and drinking intensity on drinking days (1 = moderate drinking [1–3 drinks for women, 1–4 drinks for men], 2 = binge drinking [4–7 for women, 5–9 for men], and 3 = HID [8 + for women, 10 + for men]). Results: Young adults reported higher positive affect on drinking days and higher negative affect on nondrinking days. On days when young adults reported greater enhancement motives, positive affect was strongly related to HID. During the early COVID-19 pandemic, young adults were more likely to report drinking, but did not drink more heavily unless they also reported drinking for social motives. Conclusions: These results suggest that heightened social, coping, and enhancement motives are risk factors for drinking in young adults. They also suggest that young adults perceive their mood to be better on drinking days, particularly when they were drinking to enhance positive affect. Results are consistent with a positive affect regulation model (i.e., drinking to increase positive affect), but not a negative affect regulation model (i.e., drinking to cope with negative affect). (PsycInfo Database Record (c) 2021 APA, all rights reserved)