This paper contains details extracting esters from oil of Argemone mexicana using transesterification technique. However, weed crops as A. mexicana seed oil and its seed oil methyl ester have not been tested for their production potential, comparative fuel qualities with diesel and economic feasibility. The average oil yield has been found 35%. To the author's best knowledge, this is the first study on A. mexicana seed oil and methyl ester production as a fuel. In this study, A. mexicana crop pattern and potential of seed production in field conditions, oil extraction process from the seeds and the transesterification process for ester production were examined. Seeds were collected from the crop, which was grown over a selected land area. A. mexicana seed oil was extracted and its physical and chemical characteristics determined. The produced A. mexicana seed oil methyl ester was characterized by exposing its major properties. Methyl ester yield, fuel properties and economic assessment of the oil and its methyl ester were determined and compared to that of commercial diesel fuel. The analysis of the properties in comparison to commercial diesel fuel showed that transe-methylation improve the fuel properties of the oil. (C) 2009 Elsevier Ltd. All rights reserved.