Several recent studies have identified the significant role social trust in regulatory organizations plays in the public acceptance of various technologies and activities. In a cross-cultural investigation, the current work explores empirically the relationship between social trust in management authorities and the degree of public acceptability of hazards for individuals residing in either developed or emerging Latin American economies using confirmatory rather than exploratory techniques. Undergraduates in Mexico, Brazil, and Chile and the United States and Spain assessed trust in regulatory authorities, public acceptance, personal knowledge, and the risks and benefits for 23 activities and technological hazards. Four findings were encountered. (i) In Latin American nations trust in regulatory entities was strongly and significantly (directly as well as indirectly) linked with the public's acceptance of any activity or technology. In developed countries trust and acceptability are essentially linked indirectly (through perceived risk and perceived benefit). (ii) Lack of knowledge strengthened the magnitude and statistical significance of the trust-acceptability relationship in both developed and developing countries. (iii) For high levels of claimed knowledge, the impact on the trust-acceptability relationship varied depending upon the origin of the sample. (iv) Confirmatory analysis revealed the relative importance of perceived benefit over perceived risk in meditating the trust-acceptability causal chain.