The effectiveness of density to yield of maize hybrid LVN68 in the South provinces of Vietnam. The experiments of density on maize hybrid variety LVN68 were conducted in cropping seasons of from 2010 to 2012 at Trang Bom district, Dong Nai province, Duc Trong distric Lam Dong province and Tan Chau district, An Giang province. Four densities of 55.5, 59.5, 66.6 and 75.7 thousand plants/ha were experimented on LVN68 variety. The results showed that LVN68 gave highest yield and higher than the check at of 66.6 thousand plants/ha. LVN68 variety gave highest yield at density of 66.6 thousand plants/ha.