Yield losses due to drought is an important issue in tropical maize growing regions and those losses can be more severe when the water deficit coincides with the phenological stage of flowering. Knowlegde of relationship in terms of performance between parental lines and their maize hybrids is an important goal of maize-breeding programs. The main objectives of this study were to: i) evaluate the agronomical performance of commercial maize hybrids and their parental lines under well-irrigated and drought stress environments, and ii) study the relationships between parents and maize hybrids using nine agronomical traits and multivariate techniques for each environment. Twelve maize hybrids, their eigtheen parental lines, and two-drought tolerant and one-susceptible lines as checks were evaluated under irrigation and drought stress conditions in four locations of Mexico during 2003. Hybrids and lines were evaluated in separated experiments, each type of germplasm was evaluated in side-by-side experiments under irrigation and induced drought stress per location. The experimental design was a randomized complete block with three replications for both hybrids and lines. Significant differential responses under irrigation and drought stress were observed in hybrids and lines. The maximum grain yield reductions caused by the drought stress were of 69 and 73% for lines and hybrids, respectively. In some cases, the best hybrids under drought corresponded to a good performance of their parents under same condition.