he purpose of this study is to investigate factors affecting tax audit effectiveness on large taxrnpayer’s office. The study stands to answer the following research question “How do audit quality,rnmanagement support, organizational setting, auditee attributes, organizational independence andrnthe interplay among them, influence audit effectiveness in LTO?†In light of this objective thernstudy adopted mixed research method of research approaches to test a series research hypothesis.rnSpecifically, the study used survey of questionnaire analysisoffices’ on tax auditors and interviewrnanalysis on team leaders and process owners. Then tax auditors and team leaders were selectedrnbased on simple random sampling method of census method. Because, the target population to bernstudied is small. In large tax payer’s office there are 62 tax auditors supervised and lead by 10 teamrnleaders managed by two process owners. Then the researcher distributes those questioners to the 62rntax auditors, only 59 of them are returned. Consequently,rnDatarnwasrnthenrnanalyzedrnonrnquantitative basis using Pearson’s correlation, linear regression analysis and descriptivernstatistics. Qualitatively interview and documentary evidences summarized and presented. Thernresults showed that there is no statistical significance negative relationship between auditeernattributes and tax audit effectiveness. Besides, the results showed that Tax Audit Effectiveness ofrnLarge tax payer’s office is highly affected by audit quality of the department, managements supportrnand the organizations independence from unethical practices. While as auditors perception itrndoesn’trnbernaffectedrnbyrnorganizationalrnirnsettingrnandrnauditeesrnattribute