Abstract: Chlorophosphonation of decane was carried out. After esterification of the product with ethanol the compositions were analyzed by GLC (PEG 6000, 200°C, N2 gas carrier), in comparison with authentic samples synthesized by other methods.The esterified product under conditions; 1 : 5 for the mol ratio of decane to PCl3, 200ml/min of the oxygen flow rate, -20 to 10°C for the temperature, and 5hrs for the time; was a mixture of 4.6% diethyl decane-1-, 16.8% diethyl decane-2-, 24.4% diethyl decane-3-, 29.4% diethyl decane-4-, and 24.6% diethyl decane-5-phosphonate, by GLC analysis.