Purpose. Using the example of a clinical case to show the difficulty of differential di-agnosis of lung tumors and tuberculosis, especially in coexistence. Materials and methods. The clinical observation of a combination of tuberculosis and typical carcinoid of lower lobe of left lung at the same locus is given. Results. The current clinical observation clearly demonstrates the difficulties of diag-nostics of tuberculosis and lung cancer in coexistence, also a demand of additional diagnos-tic actions for a valid verification of diagnosis in the current clinical case is shown. Conclusion. Combination of tuberculosis and lung cancer remains an up-to-date con-troversial issue in medical community. Difficulties in diagnosing due to the possibility of these diseases' manifestation in poor symptoms and similarity of the x-ray patterns, as well as changes in the concepts of coexistence and mutual influence of these pathologies en-courage interest in finding and choosing new optimal and effective diagnostic methods.