Tax revenue seems to be the most consistent government revenue and it is believed that tax audit will bring in more taxpayers into the tax web. On this premise, the study target is to discover the relationship among tax audit and tax revenue. The survey research design was relied on using the questionnaire for the collection of data from the Rivers State and Bayelsa Internal Revenue Services and the Federal Inland Revenue Services officials. Questionnaires were self-distributed and also involved proxy distribution. Randomly distributed questionnaires were returned by sixty respondents. The descriptive (pie chart, percentages, mean, SD) and the PPMC were used. The result posted a significant value of 0.000 for the two hypotheses and Pearson correlation of 0.677 and 0.575 for hypotheses 1 and 2 respectively. This means that there is a relationship that is significant exists between field audit and tax revenue and also between desk audit and tax revenue. The result further indicated that both field audit and desk audit have positive and moderate relationship with tax revenue. The recommendation from the study is that tax audit must be a consistent exercise in order to make more or increase revenue through the various taxes. It concludes that relationship that is significant exists between variables of the study (tax audit and tax revenue).