There have been great political, social and economic changes in Bulgaria since 1990 with higher incidences of syphilis when compared with the previously controlled morbidity of syphilis. There has been a 7-fold increase in 1998 compared with 1990. The male/female ratio remained the same 1.2:1. A higher number of cases was reported in cities than in villages and small towns, 80.68% in 1990; 73.4% in 1998. The number of employed patients with syphilis has decreased during the years--from 75.5% in 1990 to 44% in 1998, with a corresponding increase in syphilis in the unemployed. The age group at highest risk is 20-24 years, 28.7% in 1991; 24% in 1998. The least affected group are those older than 55--the incidence being 6.34% in 1990; 2.6% in 1997 and 4% in 1998. The prevalence of the different stages of early infection remained the same. The incidence of congenital syphilis increased from 1 in 1990 and 1991 to 21 in 1996, 29 in 1997 and 35 in 1998.