Objective: To quantify the heterosis in physical and physiological characteristics in seeds of simple and trilinear crosses of the HAZUL 10E corn hybrid. Methodology: Seeds of the genotypes conforming to the HAZUL 10E corn hybrid (endogamic lines and simple and trilinear crosses) were used. The experimental design was completely randomized with three repetitions. Physical (weight, width, thickness, length, volume, density, and the width/length and thickness/ length ratios) and physiological (normal and abnormal seedlings, death seeds, and lengths and dry matter of plumule, radicle, and total) characteristics of the seeds were evaluated. Heterosis and heterobeltiosis were determined, and the differences between both crosses were statistically tested with Student’s t-test. Results: Heterosis and heterobeltiosis were higher in the single cross than in the trilinear one. In the single cross, the highest values of both heterosis corresponded to the plumule, radicle, and total dry matter; followed by weight and volume seed. In the trilinear, the highest values corresponded to normal seedlings, radicle length, and biomass total. The variables corresponding to shape seed, normal seedlings formation, and radicle elongation, responded better to hybridization in the trilinear cross. Study limitations: None presented. Conclusions: In the single cross, heterosis increased the seed size and accumulated biomass in seedlings; while in the trilinear cross, it affected the shape of the seeds and the produced seedlings.