BACKGROUND: We determined the prevalence and factors associated with hyperlactatemia among HIV patients admitted on the emergency ward of a national hospital in Uganda. OBJECTIVE: We were specifically interested in knowing whether there was an association between clinically significant hyperlactatemia and concurrent antiretroviral therapy (ART) use. METHODS: A cross sectional descriptive study enrolled 303 HIV infected patients at a national referral hospital between March and April 2008. We consecutively recruited all eligible HIV infected patients above 18 years admitted on the emergency ward. Data were collected on socio-demographic, clinical and laboratory characteristics. Lactate levels were measured using the Accutrend(R) portable lactate analyser. Data analysis was performed using Stata 10.0; P-value of <0.05 was considered to be significant. RESULTS: Three hundred and three HIV infected patients were recruited. Prevalence of hyperlactatemia (lactate >/=2.5mmol/L) was 252 (83.2%). Clinically significant hyperlactatemia (lactate >/=4mmol/L) was present in 105/303(34.6%) patients. There was no association between use of ART and clinically significant hyperlactatemia. In the multivariate analysis, body weakness 1.91 (1.09-3.35), skin rash 3.18 (1.11-9.10) and tachypnoea 1.04 (1.01-1.07) were independently associated with clinically significant hyperlactatemia. CONCLUSION: There was a high prevalence of clinically significant hyperlactatemia among HIV infected patients but it was not associated with concurrent antiretroviral use.