Relevance. The relevance of this study is due to the high incidence of late clinical forms of syphilis in patients, who were previously treated for syphilis. Objective. The objective of the investigation was to assess the quality and effectiveness of clinical and serological control after treatment of patients with syphilis. Material and methods. Analysis of 825 case-records of outpatients with various forms of syphilis, who were deregistered after treatment and subsequent clinical and serological follow-up during the period from 1997 to 2014. Results. We traced the dynamics of changes in the regulations governing the procedure of clinical and serological control and deregistration of patients with various forms of syphilis during the studied period. We have found that there is increased proportion of deregistered patients with positive non-treponemal tests and patients who were deregistered without final serological test since they could not be found. It was founds that patients undergoing deregistration are often not examined by medical specialist and rarely undergo liquorologic tests. Conclusions. Clinical and serological monitoring does not fulfill the function of detection of late neural and visceral changes in patients with a history of syphilis. Moreover, the informativity of the control has decreased over the past 20 years. We reported our considerations on the improvement of the procedure of monitoring of these patients.