Type 1 diabetes (T1D) management is challenging during early emerging adulthood when youth experience heightened negative emotions while managing diabetes in new social settings that are increasingly separate from parents. Higher daily diabetes stress may generate affective reactions, such as higher negative affect (NA) and lower positive affect (PA), which may disrupt self-care behaviors and impair glycemic control. The present study drew on data from a larger longitudinal study that utilized daily diary and survey methods to examine if: 1) within-person fluctuations in daily diabetes stress are associated with fluctuations in daily affect (PA or NA); 2) between-person differences in T1D management (i.e., adherence or HbA1c) are associated with average levels of daily affect; and 3) individuals who display better T1D management also demonstrate lower levels of stress-related shifts in affect. Early emerging adults with T1D who had been diagnosed for more than one year (N=198; 68.2% female; Mage=18.81) completed a survey measure of adherence, an HbA1c assay, and a 14-day end-of-day daily diary assessing NA, PA, and the frequency of diabetes stressors experienced in the last 24 hours. Multilevel modeling revealed within-person associations of daily diabetes stress with daily affect, indicating that on days with higher than one’s average level of diabetes stress, participants displayed increases in NA and decreases in PA. Additionally, between-person level results indicated that individuals with better T1D adherence displayed higher average levels of PA, lower average levels of NA, as well as greater stress-related shifts in both NA and PA. Individuals with better HbA1c also displayed higher average levels of PA but did not display differences in average levels of NA nor in stress-related affect. Taken together, results indicate that regulating both NA and PA when experiencing the ongoing stress and hassle of managing T1D may be important during early emerging adulthood, an understudied but high-risk time for T1D management.