New diphosphonate compounds and related derivatives were synthesized and investigated for their activity in specifically inducing plasma high density lipoproteins (HDL) and high density lipoprotein cholesterol (HDL-C) in normal rats. The screening of numerous compounds has permitted the determination of the structural variations leading to optimal plasma lipid altering activity, indicating antiatherosclerotic potential. Among the compounds observed to be the most active, dimethyl alpha-(dimethoxyphosphinyl)-p-chlorobenzyl phosphate (20, SR-202, mifobate) was selected for further pharmacological and subsequent clinical development.