Rise in the global population, industrialization and urbanization together with increasing global trade and production facilities increase the demand for energy and natural resources every other year. Meeting the energy need arising from increasing industrialization, population growth and urbanization is reasonably the initial requirement of a sustainable development. Due to the start of rapid depletion of fossil fuels, alternative energy sources have undertaken a crucial role in producing energy. One of them is biodiesel. In production process of biodiesel via transesterification, one of the most vital parameters affecting the production efficiency is the catalyst that is used. Homogeneous and heterogeneous catalysts are utilized in biodiesel production. A number of factors such as saponification, spending great amount of reactive and extra dissociation cost have negative influences on production cost. Because of these reasons, efforts to develop high heterogeneous catalysts to hinder saponification, and the ones with high efficiency and possessing reusability have gained great acceleration and significance nowadays. In this study, using cheap and local waste eggshell as catalyst and the efficiency of biodiesel obtained in different reaction times and the effect of density and viscosity parameters were investigated. In the optimization studies (3-hour reaction time), the efficiency of the biodiesel obtained as a result of the first use of the catalyst was 94,82%, the density was 887kg / m3 and the viscosity was 4,965mm2 / s. The results obtained in the second and third uses of the catalyst were 93.43%, 890 kg / m3, 4.962 mm2 / s and 91.96, 889 kg / m3, 4.968 mm2 / s, respectively. The study was detailed by means of analysis methods such as XRD and P-XRF. The results obtained suggest that waste eggshell can be used as catalyst, and that this can have great effect on biodiesel efficiency and that waste eggshell catalyst can be reused and that it can particularly reduce the biodiesel cost significantly.