The purpose of this study was to analyze the spread of tuberculosis in Kudus Regency. One of the analyzes that can be done is making a mathematical model of SIR. The SIR mathematical model describes uninfected and susceptible individuals who are infected and can transmit the disease to a number of other individuals (infectious) and individuals who have recovered or are free from disease (Recovered). From 2018 to 2019 according to the Health Profile of Kudus Regency, the spread of tuberculosis that occurred has increased in all cases, namely the number of tuberculosis sufferers in Kudus Regency reached 3,133 patients, and the number of individuals who recovered reached 589 people. Based on the analysis of the SIR model, it is found that the equilibrium point (S, I) = (52632, 8614230) will be stable when R0 > 1, with the final conclusion, the basic reproduction rate is obtained, namely R_0 = 1,6367 which indicates that one infected individual can infect 2 people on average or individuals susceptible to tuberculosis.