The Great Akaki River crosses a predominantly residential and commercial center of Addis Ababa. Alongrnthe way, it is exposed to a variety of disturbances. In its southern section, it is exposed to industrialrneffluents. There has been some effort to assess the quality of water in the river based on chemical criteria.rnHowever, studies to assess the biological integrity of the Great Akaki River using macroinvertebraternbioassessment protocols are lacking. The Great Akaki Macroinvertebrate Index (GAMI) was developedrnfrom data collected at eight sites in the Great Akaki River from February 2006 to April 2006. Twornreference sites thought to represent natural conditions were selected from upstream. Six other sites werernselected based on the prominent land use and discharge of point and non-point sources. Thirteen metricsrnrepresenting richness, composition and tolerance/intolerance measures were considered for the indexrndevelopment. Of these, four metrics were found to be useful because they provide unique information,rnhave measurably different values in known reference sites versus known impaired sites. The core metricsrnincluded: number of taxa, number of Diptera, percent Ephemeroptera and percent dominant taxon. Thernmetrics were scored on a continuous scale from 0 (poor) to 10 (good) using the upper and lower thresholdrnof their distribution in the reference and test sites. To develop GAMI, the metrics were added and scaledrnto produce a score from 0-100. The GAMI was quadrasected to four integrity classes using 60% of thernmaximum observed value as the mark between good and poor sites. The reference sites GA1 (GAMIrnscore=99.3) and GA2 (GAMI score=70.3) were rated as very good and good, respectively. GA3 with arnGAMI score of 53.3 was rated as poor while GA4, GA5, GA6, GA7 and GA8 with a GAMI score of 30,rn29, 2.3, 20 and 0, respectively, were classified as sites with very poor integrity. The GAMI was effectivernfor distinguishing between differentially impacted sites. A Spearman correlation analysis showed thatrnmetrics expected to decrease with perturbation had strong negative relationship with nutrients and organicrnloading. Change in the structural and functional organization of macroinvertebrates was attributed to lowrndissolved oxygen, nutrient enrichment and availability of food. The major sources of these stressors werernraw sewage from households, runoff from impervious surfaces and riparian habitat degradation. Thernresults also demonstrated that the rapid bioassessment protocol for benthic macroinvertebrates is effectivernfor use in Great Akaki River