BACKGROUND: No studies have evaluated the day-to-day variations in urinary incontinence (UI) and fecal incontinence (FI) among adults with spina bifida (SB). We aimed to 1) describe variations in UI/FI over 30 days, 2) assess factors associated with anxiety about incontinence, and 3) correlate anxiety about incontinence and health-related quality of life (HRQOL) among adults with SB (exploratory). METHODS: Adults with SB participated in a larger 30-day smartphone-based ecological momentary assessment (EMA) study of well-being and incontinence. We analyzed baseline demographics, temporal variables (baseline UI/FI, incontinence, and anxiety on days prior), and incontinence episode-specific variables (number of daily episodes, incontinence interval, quantity). Urinary and fecal incontinence-related anxiety (UIA/FIA) was measured on a 5-point Likert scale ("How anxious were you because of urine/stool leaks today?"), HRQOL with QUALAS-A (scores range 0-100, 0 = lowest HRQOL). Mixed-effects, random intercept ordinal and linear regression was used. RESULTS: Eighty-nine adults participated at a median age of 33 years old (71 % female, 53 % shunted, 49 % community ambulators). Participants contributed 2578 total diary days: 61 % were associated with any incontinence (41 % UI only, 6 % FI only, 13 % both). Eighty-two (92 %) adults reported UI on a median of 16 days, but experiences varied: 6 % had a single episode, while 33 % had UI on 28-30 days (Summary Figure). Seventy adults (79 %) reported FI on a median of 5 days, less frequently than UI (p < 0.001), but experiences varied: 11 % had a single FI episode, while 31 % had FI on 10 or more days. Fewer participants reported any UIA than FIA (50 % vs. 72 %, respectively, p < 0.001). On multivariate regression, (1) higher UIA was reported by individuals with higher baseline UIA, higher UIA on days prior, multiple daily episodes and higher UI quantity (p ≤ 0.02), while (2) higher FIA was reported by those with lower baseline HRQOL, fewer FI episodes on days prior, higher FIA on days prior, and higher UI quantity (p ≤ 0.02). FIA was correlated with lower end-of-study HRQOL (p = 0.03). DISCUSSION: Instances of incontinence are not uniform experiences. Their effects vary with factors beyond the actual episode. This suggests novel potential points of intervention to improving long-term HRQOL among people with incontinence. CONCLUSION: Day-to-day experiences of UI and FI vary among adults with SB across multiple dimensions. Anxiety about incontinence when it occurs varies not only based on individual- and episode-specific characteristics, but also on incontinence in the preceding days. Operationalizing these insights into potential clinical interventions warrants further investigation.