This work proposes to analyse the quality of the failure risks in the case of a short duration treatment applied in operational conditions on the territory of Constanţa County as a premise for the application of a method of mathematical analysis on computer in view of predicting the failure cases. There were studied 262 eligible cases out of 290, which represent the total of the patients newly registered with pulmonary tuberculosis in 1982, on the territory of Constanţa County and who were kept an eye upon for 3 years after finishing the treatment. There resulted 58 (22.1%) recurrencies, failures or corrected in course intratherapeutic positive reactions, on which were analysed 25 possible failure factors. The most representative have proved to be the organizational factors among which irregular treatment (67.2%) of the failure cases, a defective mobilizing to treatment, technical factors: late negativation of sputum (over 4-5 months from starting the treatment), and among the factors depending on the patients--noncooperation occurred in 60.33% of the failure cases. If the final frequency of failures on the territory of Constanţa County does not exceed the average figures recorded here and abroad, the global frequency within the studied time period is not satisfactory and imposes an assessing of the failure factors and measures of improvement.