Abstract: Background and Objectives: Delay seed germination, Seedling vigor and mortality due to seed borne pathogens are causing increasingly the economic losses in chilli. The experiment was conducted to determine the effect of H2O2 on seed health, germination and vigor of chilli seeds. Materials and Methods: The experiment was carried out in the laboratory of the Department of Plant Pathology, Patuakhali Science and Technology University, Patuakhali, Bangladesh. There were 4 treatments viz. water soaked seeds, seed treated with 1% H2O2, seed treated with 2% H2O2 and seed treated with 3% H2O2. The experiment was conducted by Completely Randomized Design (CRD) with three replications. Data were analyzed using one-way ANOVA with the Web Agri Stat Package 2.0 (WASP). Means were compared by the Duncanʼs multiple tests and statistical significance was determined at 5% level. Results: Six fungal species were isolated from treated and untreated chilli seeds. Isolated fungi were Aspergillus flavus, Rhizopus stolonifer, Colletotrichum capsici, Curvularia lunata, Alternaria alternata and Fusarium moniliforme. The highest 50.74% mycelial growth inhibition of Aspergillus flavus was obtained by 3% H2O2 treatment. For 1% hydrogen peroxide treated seeds the germination percentages were 55.47, 60.53 and 84.80% at 7, 10 and 15 Days After Sowing (DAS), respectively. The maximum root length 4.767 cm was found in seedling raised from seeds treated with 1% H2O2. Significantly higher shoot length (2.769 cm) was obtained from the seedlings raised from 1% H2O2 treated seeds. The highest 640.7% vigor index was recorded in seedlings obtained from 1% H2O2 treated seeds. Conclusion: The treatment of chilli seeds with hydrogen peroxide, regardless of concentration, significantly reduced seed infestation with seed borne and improved health of chilli seeds. Among the concentrations of H2O2, 1% H2O2 is more effective in increasing seed germination percentage, vigor index and percent inhibition of mycelial growth.