Lead exposure is common in automobile battery manufacture and repair, radiator repair, secondary smelters and welding units. Urinary Aminolevulinic acid has validity as a surrogate measure of blood lead level among workers occupationally exposed to lead. This study had therefore assessed the magnitude of lead exposure in battery repair workers of three transport service enterprises. To this effect, a cross-sectional study was carried out on lead exposure among storage battery repair workers between November and May 2005 from Anbasa, Comet and Walia transport service enterprises, Addis Ababa, Ethiopia. Subjective information from the workers was obtained by making use of structured questionnaire. Other information was obtained from the walkthrough evaluation of the repair units. Aminolevulinic acid levels in urine were used as an index of the exposure. This was coupled to measurements of other relevant parameters in blood and urine collected from adult subjects working in the repair units as well as age matched control subjects that were not occupationally exposed to lead. Aminolevulinic acid was determined by spectrophotometry, while creatinine clearance, serum creatinine, urea and uric acid levels were determined using AMS Autolab analyser. Urinary Aminolevulinic acid levels were found to be significantly higher in exposed group (1.6 mg/dl+ 0.2) compared to the non-exposed ones (0.7mg/dl+ 0.1) (p<0.001). Alcohol taking exposed subjects exhibited a significant increase in urinary aminolevulinic acid levels than non-alcohol taking ones (p < 0.05). Moreover, urinary aminolevulinic acid levels of exposed subjects increased with age (p<0.001) as well as duration of employment (p<0.001). Whereas, serum uric acid levels of exposed subjects was significantly higher than non-exposed ones (p<0.05), no statistically significant difference had been found in renal indices and other measured parameters between exposed and non-exposed subjects. From the questionnaire responses and walkthrough observations, it was known that all the repair units do not implement effective preventive and control measures for workplace lead exposure. Taken together, these findings indicated that workers in lead acid battery repair units of the transport service enterprises are not safe from excessively high lead exposure. Thus, strict enforcement of appropriate and cost-effective preventive and control measures is required by all the enterprises. Key words: Lead exposure, Delta-Aminolevulinic acid, renal indices, uric acid, preventive and control measures