The first objective of this study was to detect QTLs affecting agronomically important traits in the F2 plants of an elite, single-cross of maize (Zea mays L.). The second objective was to compare QTL detection in the F2 and F2:3 generations. The third objective was to compare QTL detection in two samples of F2:3 lines derived from the same F2 population;Thirty-eight QTLs affecting five traits were identified in the F2 plants. The QTLs were associated with 6 to 43% of the phenotypic variation. QTLs explaining more than 40% of the variation were observed for plant height and ear height. Most plant height and ear height QTLs with large effects had additive gene actions. Gene actions for flowering traits included additive, partial dominance, dominance, and overdominance. The parental effects were usually in accordance with the phenotypes of the inbred parents. Ten digenic interactions were observed, 2 for plant height and 8 for anthesis. One dominant x additive interaction affected a plant height QTL;Eighty-six QTLs were detected across F2 and F2:3 generations. More QTLs were unique in the F2:3 than in the F2 generation. Evidence of consistent detection was observed at 22 of the 86 QTLs. Most QTLs that were common in the F2 and F2:3 generations had intermediate to strong association with phenotypic variation. Most parental effects were conserved across generations, but the magnitude of effects was usually smaller in the F2:3.;Sampling variation influenced QTL detection across samples. Ninety-three QTLs were detected for plant stature and flowering across samples. Evidence of consistent detection was observed at 27% (25 of 93) of the QTLs. For grain yield and yield components, seventy-one QTLs were detected across samples, only thirteen were common in both samples. Chromosome 6 was significantly associated with grain yield in both samples. The magnitudes of QTL effects were not always consistent when QTLs were detected in a region for both samples. Most QTLs detected in both samples had the same parental effects.