A case-control study of sexun lly t r:l n s mitt ed di ~e as es wa srncarried out in two h e a l th uni.ts in Gondar Town no rth-w es t e rnrnEthiopia between Se ptemb e r 1987 and November 19 8 7. A totalrnof 285 cases and 570 controls participated in th e study.rnThe peak age range was 15 - 19 yea r s (43.9%) and 20-24 year srn(34.6%) for female and mal e case s r es pectively. In con trastrnto reports from other parts o f Afrj~R, th e male-tofemalernratio was 1.2:1 i n t his s t ud~Â· . Over 40 [: o f therncases were found in Ke ft pgnn four in whi ch there are predominantlyrnsoldiers and pros titu tes. Of 153 mal e cases,rnonly 26.2% were married. Ma rri ed women constituted 33.1%rnof t he cases. While a further 33 . 3% wprA di.vorc ed womAn.rnSoldiers, prostitut e s and s tudent s (28.8 %, 19.7% and 13.3%rnof the total cases respectively) were identified as highrnrisk groups. The commonest diagonsis was gonorrhoea (56.5 X),rnwith further 21.8% of the mixed infections including gonorrhoea.rnOver 40% of the case s admitted to a previous historyrnof STD. A past history of four or more STD inf ection s occurredrnin 10.9% of the total cases. Casual contact orrnunknown contact as a source of infection accounted for 50%rnof the infections rivalling prostitutes who accounted forrn52.3% of the contacts. Of the total cas es, 54.4% soughtrna cure from druggists without see ing a h e al t h worker .rnThe practice of self-medication was high and did not appearrnto differ greatly between educat ed and illite rat e groupsrn(P>.lO) .rnAge at first sexual intercourse of l ess than 20 y ears wasrna s sociated with a statis ti c :llly s i g ni f i ca n t inCr0:lSed ri s krnof STD (OR mh = 3. 6 , P