The future of fossil fuel sources of energy has necessitated the need to search for renewable alternatives. Thus, Carica papaya seed oil (CPSO) was employed as feedstock for the production of biodiesel by methanolysis. The seed was obtained locally, dried, and extracted with n-hexane. The CPSO was analyzed for specific gravity, viscosity, iodine value, and saponification value, among others using standard methods. The oil was transesterified by two-stage catalysis with oil to methanol mole ratio of 1？:？9. The biodiesel produced was subjected to standard fuel tests. The seed has an oil yield of 31.2% which is commercially viable. The kinematic viscosity of the oil at 313？K was 27.4？mm2s？1 while that of Carica papaya oil methylester (CPOME) was reduced to 3.57？mm2s？1 and the specific gravity was 0.84 comparable with other seed-oil biodiesels and number 2 diesel. Other oil properties were compared favourably with seed oils already documented for biodiesel synthesis. CPOME’s cloud and pour points were 275？K and 274？K, respectively, and relatively higher than other biodiesels and number 2 diesel. CPOME exhibits moderate corrosion of copper strip. The methanolysis improved the fuel properties of the CPOME similar to other biodiesels. CPSO therefore exhibits a potential for biodiesel production. 1. Introduction The major parts of all energy consumed worldwide come from fossil sources (petroleum, coal, and natural gas). However, these sources are limited and nonrenewable and will be exhausted in the future. The price volatility of fossil-based fuels, monopoly in the crude-oil market, energy crisis associated with technological advances are some of the justifications for continuous quest and renewed drive for alternative, cheaper, and renewable energy sources [1, 2]. There is a global clamour for sustainable development and environmental conservation. This has also increased the tempo of researches on the application of biotechnology for other sources of fuel [3]. Thus, there is global interest in sourcing for eco-friendly, clean-burning, and renewable alternative sources of energy such as energy from biomass, wind, solar, hydroelectricity, geothermal, and hydrogen, among others. Alternative and renewable fuels have the potential of solving many of the current social problems and concerns, from air pollution and global warming to other environmental improvements and sustainability issues [4]. Furthermore, over dependency on petroleum reserves for energy supply and the increasing demand for energy are indicators that supply will not meet demand with time. There
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