Laboratory and field experiments were conducted to evaluate the accuracy of different seed vigor tests for prediction of onion seed performance in field. Seed vigor tests under evaluation were accelerated aging (24, 48 and72 h), salt saturated accelerated aging (24,48 and 72 h) , controlled deterioration and brick gravel test, beside standard germination test. Accelerated aging at 48 h and controlled deterioration tests showed insignificant differences with field emergence % and provided the same classification of the onion seed lots found by the emergence of seedlings in the first season.  But, standard germination test and other vigor seed tests recorded significant differences of quantitative relation with field emergence %. Standard germination test, accelerated aging 48 h, controlled deterioration and brick gravels tests were a significantly contributing variables to variation in field emergence % according to simple regression analysis. But, we had not reliability of  the simple regression analysis to evaluate seed vigor tests for  prediction of onion seed performance in field. It could be concluded that the prediction of field emergence of onion seed can be effectively done by using accelerated aging 48 h and the controlled deterioration tests, for standardization accelerated aging 48 h and the controlled deterioration tests for field emergence prediction of onion seed lots, they should be tested in different laboratories.