Chlorophosphonations of n-alkyl acetates (CH3COOR; R=C3C8) were carried out and the products were analyzed with GLC, using 3m×3mmφ, Ucon LB 550X column, and identified by comparing their retention times with those of authentic samples synthesized by other methods. The compositions of the products were determined. The results were expressed with relative reactivities per hydrogen at methylene groups to the terminal methyl group as standard, as shown in Table. The substitution of dichlorophosphinyl group on the acetyl group did'nt occur.