This study aims to determine how the calculations, cutting, collecting, depositing and reporting of income tax under Article 21 of PT. Sentosatama Indah Abadi – Dumai. Research methods used in collecting file is the observation, interviews, primary file and secondary file on the PT. Sentosatama Indah Abadi – Dumai. The results found that the PT. Sentosatama Indah Abadi - Dumai has done th…