An experimental investigation has been carried out with the objective of evaluating the physicochemical characteristics and the effect on CO, HC, and CO2 emissions when using different biodiesel blends from algae oil. For the study, different operating conditions have been defined in a single-cylinder diesel engine, in which the load has been varied at a torque level of 2 Nm, 4 Nm, 6 Nm, and 8 Nm. In addition, a change in the compression ratio of 16, 18, and 20 has been made. Biodiesel blends have been prepared in different percentages of algae oil, identified as AB4, AB8, and AB12. For a percentage of algae oil biodiesel between 4-12%, a 1.82% reduction in calorific value, and an increase of 0.89% in fuel density have been obtained when compared to commercial diesel. Operating conditions with a compression ratio of 20 have allowed less formation of CO, HC, and CO2 emissions. The use of algae oil in diesel allows a decrease in the levels of CO, HC, and CO2 by 35.09%, 45%, and 26.07% compared to commercial diesel. However, the addition of a substance such as algae in the fuel facilitates the formation of NOx due to its additional oxygen content.