This investigation was conducted during 2003 season at Seed Technology Unit in Mansoura, Dakahlia Governorate, Egypt. The study aimed to determine the value of some laboratory tests (electrical conductivity, accelerated aging, germination %, speed of germination, germination rate index,  plumule and root length (cm), and seedling dry weight(g) to estimate seeds vigor of three varieties of rice ( 7 lots/ variety). The results declared that electrical conductivity test and germination test gave a similarity results with those obtained by field emergence and showed significant differences between all lots in three rice varieties of Giza 178, Sakha 101 and Sakha 104. On the other hand, accelerated aging, speed germination, germination rate index, plumule and root length and seedling dry weight showed no variation with field emergence and non significant  differences between the lots of three rice varieties. So that, this study concluded that application of  electrical conductivity test, germination test and field emergence were valuable tests to determine  seeds vigour of  rice lots.