The aim of the study is to investigate the effects oils vegetable blends on the performance of single cylinder compression ignition Engine. The three types of vegetable oil appeared to affect the engine performance in a similar way and compared well with diesel fuel, this paper included prepared four samples fuels . They include (10% sunflower oil- 90% diesel blends) , (10% olive oil – 90% diesel blends), (10% corn oil- 90% diesel blends) and pure diesel . The testing achieved between different fuel simples by using the engine four stroke type (TD111) with a single-cylinder and compression ratio (21:1) . The results show that there is decreasing in parameters performance of engine with using vegetable fuel blends , the brake power decrease as (7.4% ),(5.2%) and ( 1.3%) with using the samples (10% olive oil – 90% diesel blends) , (10% sunflower oil- 90% diesel blends) , and (10% corn oil- 90%diesel blends) respectively compared with pure diesel fuel for the engine speed of 2000 r.p.m. .While at same engine speed the ηbth showed a decrease as (10.9 %),(7.5%) and ( 5.8%) with using the (10% olive oil – 90%diesel blends) , (10% sunflower oil- 90%diesel blends) , and (10% corn oil- 90%diesel blends) respectively compared with pure diesel fuel . At the same time , it can be found that bsfc also increases as (7.9% ) , (5.7%) and ( 2.4%) with using (10% olive oil – 90% diesel blends) , (10% sunflower oil- 90% diesel blends) , and (10% corn oil- 90% diesel blends)compared to pure diesel fuel . The exhaust gas temperature decrease as ( 7 0C),( 5 0C)& (3 0C) with using the samples (10% olive oil – 90% diesel blends) , (10% sunflower oil- 90% diesel blends) , and (10% corn oil- 90%diesel blends) respectively compared with pure diesel fuel for the engine speed of 2000 r.p.m. .