This study examined the impact of taxpayer identification number on revenue generation in Ekiti state, over the period of 10 years covering 2006 to 2015. Specifically, the study examined the trend of internally generated revenue over the period covered and investigated the impact of full adoption of taxpayer identification number on the revenue generated in Ekiti state, using a single equation model in which revenue generation proxies by internally generated revenue (IGR) was made a function of full adoption of TIN as latent variable, alongside capital expenditure as a control variable. Ordinary least square regression estimation technique was used. The result revealed that full adoption of taxpayer identification number exerts a significant positive impact on internally generated revenue of the state, given a coefficient estimate and probability values of 5031.843 and 0.0182 respectively. It was concluded that full adoption of taxpayer identification number in Ekiti state has the capacity to spur revenue generation. Thus, it was recommended that government through the state internally generated revenue services should work out modalities necessary to ensure that all taxable persons and/or business entity collect an identification number so as to further maximize the positive impact of the TIN.