Inner and outer primer pair were designed and synthesized according to the cDNA sequence of liver type phosphofructokinase (PFK) of the mouse. A nested reverse transcriptasepolymerase chain reaction (Nested RTPCR) was used to determine the transcript pattern of mRNA encoding mouse PFK throughout 1,2,4,8cell and morulae embryos. The results showed that 1cell to morulae mouse embryos mRNA could be amplified to give an expected band using the inner primer pair on the templates provided by the products of the first PCR using the outer primer pair. These observations indicated that the transcripts of PFK gene existed and that the PFK of early mouse embryos is of the liver type. Glycolysis and tricarboxylic acid cycle (TCA) appear to be the important mode of glucose metabolism in 1cell to morulae mouse embryos.