To investigate the relationship between the ATP content in human oocytes and the developmental potential of human oocytes, unfertilized oocytes from clinical IVF and immature oocytes unsuitable for ICSI were collected. The ATP content of these unfertilized andin vitro matured eggs were determined quantitatively by measuring the luminescence using an ATP-dependent bioluminescence assay. The result showed that the ATP content of unfertilized oocytes was higher thanin vitro matured ones (2.20±0.67 pmol vs 1.72±0.49 pmol,P<0.05). In unfertilized oocytes, the ATP content of those whose fertilization rates (FR) was higher than 50% was 2.43±0.60 pmol, which was significantly different from those whose FR was less than 50% (1.72±0.56 pmol), while inin vitro matured oocytes, the ATP content of those whose FR more than 50% was 1.8±0.44 pmol, slightly higher than those less than 50% (1.55±0.40 pmol), without statistical significance. There was a tendency that the ATP content of oocytes of pregnant patients was higher than those of controls, but the sample number was too small to show any significance in statistics. Briefly, there was positive correlation between the ATP content in oocytes and developmental potential of oocytes.