BACKGROUND & AIMS: Chronic hepatitis B (CHB) and metabolic dysfunction-associated steatotic liver disease (MASLD) commonly co-exist, with conflicting data in prevalence and disease severity. We aimed to investigate these discrepancies. METHODS: This multicenter study included consecutive patients with CHB from 19 European centers. A survey on standard of care for MASLD screening in CHB was circulated. RESULTS: A total of 1709 patients with CHB were included; median age, 53 years (interquartile range [IQR], 42-64); males, 60.7%; body mass index (BMI), 25.6 kg/m2 (IQR, 14-63 kg/m2); and 57.3% White. MASLD prevalence (1510 consecutive patients) was 42.3%. BMI (odds ratio [OR], 1.27; 95% confidence interval [CI], 1.19-1.36), ferritin (OR, 1.00; 95% CI, 1.00-1.00) and type 2 diabetes (OR, 2.60; 95% CI, 1.12-6.02) were independently associated with MASLD. The prevalence of advanced fibrosis was 18% (255/1420) in the whole cohort, 25.4% (162/639) among patients with CHB with MASLD, and 13.7% in those without MASLD. Independent predictors of advanced fibrosis were MASLD (OR, 2.76; 95% CI, 1.50-5.05), BMI (OR, 1.08; 95% CI, 1.02-1.15), alanine transaminase (OR, 1.01; 95% CI, 1.00-1.03), lower platelets (OR, 0.99; 95% CI, 0.98-0.99), insulin treatment (OR, 13.88; 95% CI, 2.95-65.28), and long-term antivirals (OR, 4.86; 95% CI, 2.40-9.85). During follow-up (48 months), only patients without MASLD showed significant liver stiffness measurement improvement over time (P < .001). Among patients with MASLD, Fibrosis-4 and liver stiffness measurement performed moderately at predicting advanced fibrosis (area under the receiver operating characteristic curve = 0.71 vs 0.70; P = .38) against histology. As standard of care, 68.4% of centers screened all patients with CHB for MASLD; 52.6% followed the same treatment indication in those with CHB and MASLD vs CHB only. CONCLUSIONS: In this large European cohort, MASLD and fibrosis were highly prevalent among patients with CHB, whereas MASLD aggravated liver fibrosis. Though screening strategies remain inconsistent, ferritin levels, increased BMI, and type 2 diabetes may inform on the presence of MASLD. Biomarkers showed modest performance in predicting fibrosis.