The main goal of this article is answering the question that at what stage of the pulmonary tuberculosis the affected patients are identified and diagnosed.The result of such a study are critical as they help us with measuring out the success  or failure of identifying patients and finding out different ways of conveying the tuberculosis disease in the society. The sputum specimens of 1046 patients referred from different parts of Tehran and other parts of Iran were examined in the Zarifi laboratory. These specimens were both directly examined by the Ziehl-Nielson method and also cultured in the Lowenstein-Johnson media. However, determining the stage of the disease requires direct smear of the samples. The results of the study are summarized as follows. 14% of patients were diagnosed at the stage 1, 36% of patients were diagnosed at the stage 2, 21% of patients were diagnosed at the stage 3 and finally 29% of patients were at the stage 4. Therefore, the key point here is the unfortunate fact that 50% of patients referred to laboratories are already at the advanced stages of 3 and 4.