Background/Objectives: Patients with inflammatory bowel disease (IBD), whether affected by Crohn's disease (CD) or ulcerative colitis (UC), are burdened by disability and a reduced quality of life. The individual's regular participation in daily working life is a key factor among its determinants. This work aims to quantify work absenteeism in patients with IBD, profiling it concerning specific demographic variables, the degree of disease activity, and the level of self-reported anxious symptoms. Methods: A cross-sectional observational study targeted patients with a known diagnosis of IBD with disease activity no greater than moderate who were either employed or engaged in regular student activities. Participants were administered the Beck Anxiety Inventory (BAI) for the assessment of anxious symptoms, the Patient-Reported Outcome 2 (PRO-2) for evaluating IBD disease activity, and the Health and Work Performance Questionnaire (HPQ) short form for the analysis of work absenteeism, measured both as absolute and relative over two time frames (the last 7 days and the last 4 weeks). Within the HPQ, Likert scale (0-10) questions were administered to assess self-perceived work productivity. Results: A total of 300 patients were included [median age 43.5 years, IBD (UC 55.7%, CD 44.3%, sex (males 54%, females 46%)], recording absolute absenteeism of 56 (36-76) and 2 (-8-20) hours lost over 4 weeks and 7 days, respectively. The factors associated with worse absolute and relative absenteeism (both at 7-days and 4-weeks) were having CD (p < 0.001), having previous surgery (p < 0.05), and, exclusively in the 4-week assessment, being female (p < 0.05) and a smoker (p < 0.05). The BAI demonstrated a moderate correlation with 4-week absolute absenteeism (rho = 0.374, p < 0.001), progressively increasing with anxiety severity. Additionally, the BAI was an independent predictor of a 25% work productivity loss over 4 weeks (aOR: 1.1, 95% CI 1.06-1.142, beta = 0.096, p < 0.001). Disease activity measured based on PRO-2 strongly correlated with 4-week (rho = 0.53, p < 0.001) and 7-day (rho = 0.47, p < 0.001) absolute absenteeism. Conclusions: In conclusion, work absenteeism in IBD patients may be driven by the IBD phenotype, sex, anxiety, and disease activity. Improving these parameters could enhance productivity.