SUMMARY: A series of HIV sero-prevalence surveys have been carried out in Ethiopia within the framework of the medium term plan for AIDS Control. The surveys were designed to monitor progression of the HIV epidemic in the populations experiencing various risk behaviours as well as in the general population. Sex workers were represented by 2056 randomly selected females practicing multi-partner sexual contact (MPSC) in seven urban areas in 1988, and by 1987 persons in 1989. Similarly, 995 employees of thee Ethiopian Freight Transport Corporation (EFTC), (drivers, assistants, and technicians) were tested in 1988, and 555 in 1989. A survey was also conducted in December 1989 among 318 out patients in Assela Hospital. The average HIV prevalence rate in the country in 1988 among MPSC females was 18.5%. In the second year the average prevalence rate in the seven towns increased to 29.2%. This showed a progression rate of 57.8% in a 12 months period. The progression rates were higher in the initially low prevalence areas and vice versa (r = -0.92). Among the EFTC employees the rate of progression was 33.0% in the drivers and 78.0% in the technicians (initial prevalence rates were 17.3% and 4.1% respectively). The sero-conversion rate was 7.2 % among these EFTC workers within 12 months. No HIV sero-positive person was found among 300 hospital outpatients in Assela hospital in the 1985-86 survey while by the end of 1989 3.5% of the same population group were infected. The results of consecutive testing of blood donors also indicated that HIV prevalence has been increasing steadily, though at a lower rate than among those groups who practiced risk behaviour. These studies indicate that HIV infection is progressing among the urban population in Ethiopia. There is an urgent need for intensive health education aimed at changing sexual behaviour and at promotion of condoms in order to decrease further spread of HI