Model public health laws (public health laws or private policies publicly recommended by at least 1 organization for adoption by government bodies or by specified private entities) are promoted as exemplary. We assessed the information sponsors of model public health laws provide on the methods used in developing their models and on their models' adoption and effectiveness. Through a systematic search, we identified 107 model public health laws published from 1907 to 2004. As of our assessment in 2005, only 18 (44%) of the sponsors presented any information on the procedures and evidence used in developing their model public health laws; information on adoption was provided for only 7 (6.5%) model laws. No sponsors provided information on model effectiveness. We recommend sponsors improve their disclosure of information about the methods and evidence used in developing model public health laws and about their adoption and effectiveness.