In Ethiopia large amount of spent coffee ground are generated from various coffee houses,rnrestaurants and households a result of the high consumption of coffee. Until now, there are norncurrent profitable uses, and their adequate disposal constitutes a major environmental problem. rnThe aim of this study was optimization of reaction variables and production of biodiesel fromrnspent coffee ground oil using acid base catalyzed method. For this study, spent coffee groundsrnwere collected from different coffee houses, Addis Ababa. The collected spent coffee groundsrnwere dried in an oven at 105Â° C for 8 hours. The oil was extracted by applying a soxhletrnextraction using n-hexane and then extracted oil was converted to biodiesel using acid catalyzedrnesterification followed by alkali-catalyzed transesterification. The physicochemical properties ofrnthe extracted spent coffee ground oil were found to be oil yield (13.09%), density (898kg/mrn),rnkinematic viscosity at 40â„ƒ (45.91 mmrn3rn/s), saponification value (192.5mgKOH/g oil), acid valuern(12.2mg KOH/g),free fatty acid (FFA) (6.1%) ,iodine value (81.9 g I2/100g) and calorificrnvalue(37.74MJ/kg). The FFA in the spent coffee ground oil was reduced from 6.1 to 0.69% withrn6:1 molar ratio of methanol to oil in the presence of 3.5wt% sulfuric acid at 90min. For thernsecond step, an optimum biodiesel yield of 91.5% was obtained with 9:1 methanol to oil molarrnratio, 1.5% KOH catalyst and 90 min reaction time. The fatty acid methyl ester composition ofrnthe biodiesel produced from SCG oil was done with using GC-MS and 17.65% of saturated andrn82.5% unsaturated fatty acid methyl esters were identified. The physicochemical properties thernproduced biodiesel were found to be density (870.3kg/mrn2rn), kinematic viscosity at 40â„ƒ (4.13rnmmrn3rn2rn/s), flash point (162â„ƒ) ,calorific value(40.39KJ/kg), cetane number(57.4), acid value (0.65rnmg KOH/g and iodine value (178.5 g iodine/g). The results indicated that the properties ofrnbiodiesel produced agree with the limit ASTM D6751and EN 14214 standard. Therefore, thernstudied physicochemical properties of the waste coffee biodiesel suggest that this fuel can bernused as a fuel in diesel engines.