This study is aimed at determining and com.?aring Ihe COSI incurred in Ireating HIVIA IDSrnand non- J-IIV .-JlDS patients and the impaci ',n healih institlllions. Three hospitals in AddisrnAbaba nameh Tikur Anbessa, St. p oul's ano Zewdifll were included in this slUdy. Essentialrndata were e.Xlracted by assessing patient cO'ds and Administrative records retrospectivelyrnand filled in a format developed .flJr the purpose of this sflldy. The eXlracted data werernentered and analyzed in SPSS statistical paci-.age. The costs per inpatiel7l day, per inpatientrnstay and outpalient visits were estimrJted by wing the service and unil COSI approaches.rnThe hospital costs of 453 patients (293 HIV positire, 160 HIV negative) were analyzed thernmean length of stay of HIVIAIDS pal ients were 19 days and outpatient visils were 4 days. ThernHIVIAIDS pmient service charges paid to the hospiwl (service cost) per admission were onrnaverage Birr 1,134 (US $ 132)' ond per (~utpalient visits were Birr 585.41 (US $ 68)rnmoreover these inpatient and outpatient public services valued using private hospitals servicernprices the cost was Birr 4,614 (US 1) 539) and Birr 1,072 (US $ /25) respectively. Whereasrnthe unit cost of HIVIAIDS patients per admission were Birr 2,72 7.51 (US $ 318) and Birrrn629.88 (US $ 74) per outpatient visitsrnThere was no significance difference in cost of !reatmenl, average length of stay andrnoutpatient visilS between HIV positive and negative patients. However at the outpatient levelrnthe unit cost of treating the HIVIAIDS patienl.1 is significantly greater than the non-HIVIA1DSrnpatients.rnThe similar cost patterns of the two patient groups examined in this study may reflect the factrnthat few therapeutic options, limited and non-specific basic health services are beingrnprovided to both groups of patients. Therefore information on costs of the treatment and carernof AIDS patients in health facilities is necessary in order to have an idea of the likely costs ofrnthe increasing number of AIDS patients and to plan for their management and treatmentrneffectively.