This study examined contributions of environmental and personal factors (specifically, food availability and expense, daily hassles, self-efficacy, positive and negative affect) to within-person and between-person variations in snack food intake in 100 African American women. Participants were signaled at random five times daily for seven days to complete a survey on a study-provided smartphone. Women reported consuming snack foods at 35.2% of signals. Easier food availability accounting for one's usual level was associated with higher snack food intake. Being near outlets that predominately sell snacks (e.g., convenience stores), while accounting for one's usual proximity to them, was associated with higher snack food intake. Accounting for one's usual daily hassle level, we found that on days with more frequent daily hassles snack food intake was higher. The positive association between within-person daily hassles frequency and snack food intake was stronger when foods were easily available. Public and private policies to curb ubiquitous food availability and mobile health interventions that take into account time-varying influences on food choices and provide real-time assistance in dealing with easy food availability and coping with stressors may be beneficial in improving African American women's day to day food choices.