This study was conducted to investigate the effect of energy source on development of in vitro development of in vitro matured and fertilized porcine 2-cell embryos. The relative preferences of glucose, lactate and pyruvate for in vitro development of porcine 2-cell embryos were determined. The results obtained are as follows. 1. 33.3, 20.8 and 29.2% of porcine embryos reached morula stage in addition to lactate, glucose, and both glucose and lactate in the culture medium as energy source, respectively. 2. 38.5, 15.4 and 26.9% of porcine embryos reached morula stage in addition to pyruvate, glucose, and both glucose and pyruvate in culture medium as energy source, respectively. 3. 42.9, 21.4 and 28.6% of porcine embryos reached morula stage in addition to pyruvate and lactate, glucse alone, and glucose, lactate and pyruvate in culture medium as energy source, respectively.