Syntheses of polyethyleneglycol (PEG)-lipid conjugates are disclosed. Such syntheses involve stepwise addition of small PEG oligomers to a glycerol backbone until the desired chain size is attained. Polymers resulting from the syntheses are highly monodisperse. The present invention provides several advantages such as simplified synthesis, high product yield and low cost for starting materials. The present synthesis method is suitable for preparing a wide range of conjugates. In another aspect, the invention comprises PEG lipid conjugates having a glycerol backbone covalently attached to one or two monodisperse PEG chains and one or two lipids. These conjugates are especially useful for pharmaceutical formulations.
