The variety of explanations to questions about the origin of life, life after death or about the role itself of being in the world are built on the rational reflection that integrates the ideology of human beings as well as less rational practices and more emotional ones than in the whole nourish what has been called "beliefs". Therefore, the aim of this study was to construct an instrument to measure beliefs about the origin of life and life after death. A scale with a Likert 5-point response type was made up of 52 reagents; it was applied to 913 people of the Metropolitan Zone of Mexico City to obtain their psychometric characteristics, all whose schooling was either basic or an academic PhD degree. To identify the discriminative power of each test item, internal consistency, exploratory factor analysis and Pearson's correlation, data was analyzed using SPSS version 21. The final scale was formed by 48 reagents distributed in 4factors that threw a Cronbach Alfa of 0.874. In conclusion, these results reveal a valid and reliable instrument as well as a useful tool for studying the phenomenon of the origin of life and life after death.