This study deals with designing and validating an HPLC procedure for the determination of favipiravir and ten favipiravir-related impurities simultaneously in favipiravir bulk forms. The ten favipiravir related substances investigated herein included 6-Bromo-3-hydroxy-amide; 6-Fluoro-3-hydroxy-nitrile; 6-Chloro-3-hydroxy-amide; Favipiravir acid; 3-Hydroxy amide; 3,6-Difluoro amide; 3,6-Dichloro amide; 6-Chloro-3-hydroxy-nitrile; 3,6- Difluoro nitrile; and 3,6-Dichloro nitrile. Column Inert Sustain C18 is used to analyze favipiravir and favipiravirrelated impurities. Mobile phases employed included 20 mM KH2PO4 (system A) and 20 mM KH2PO4: Acetonitrile combined in 700:300 (vol/vol) parts (system B,) and given to column through gradient elution. The system was examined in accordance with the ICH prerequisite and was capable of providing accurate (96.4-114.8%) and precise (0.1-0.4%) quantitative results. The peak purities measures for favipiravir and its ten impurities revealed specificity. Linearity was evidenced from the LOQ amount level to 120% amount of the specification level (0.0015 mg/mL) with R 2 measures ˃ 0.999 for favipiravir and its ten related impurities. This method concluded it was beneficial for the evaluation expected.