Maize (Zea mays L.) is one of the important food security crops and play significant role in the livelihood of most Ethiopians. However, the productivity is hampered by several biotic and abiotic factors including low soil fertility. This study was therefore; conducted to determine optimum rates blended fertilizer under limed and unlimed condition of acid soil on Maize in Omo Nada District, Jimma Zone Southwestern, and Ethiopia during 2017 main cropping season. The amount of lime that was applied at each location was calculated on the basis of the exchangeable acidity. The experiment used seven treatments; Control, NPS, NPSB,NPSB plus Recommended rate of Lime, NPSB plus 0.75*recommended rate of Lime ,NPSB plus 0.50*recommended rate of Lime and NPSB plus 0.25* recommended rate of lime were laid out in randomized complete block design (RCBD) replicated across Seven farmers’ fields in each location. Application of lime was dramatically improved soil pH from 4.5 to 5.28. Yield and yield components of Maize were significantly affected by integrated use of blended fertilizer and lime. Accordingly, Plant height, Grain Yield, Biomass Yield, Harvest Index and thousand kernel weight of Maize were obtained with application of NPSB plus recommended rate of Lime. Higher net return 15914 Ethiopia birr/ha with marginal rate of return of 557 % of Maize was obtained with application of NPSB plus Recommended rate of Lime. Thus, integrated use of NPSB plus Recommended Lime is recommended for Maize production in acid soil of Omonada district and similar agro ecologies. Keywords: soil pH, soil test, fertilizer recommendation, Yield DOI: 10.7176/JBAH/11-11-03 Publication date: June 30 th 2021