Abstract: Maize (Zea mays L.) single-cross hybrids derived from 12 x 12 half-diallel crosses among selected inbred lines were evaluated for performance of the hybirds and to determine phenotypic correlations among traits. Varied estimates of broad-sense heritability (h2B) between locations were found for all characters, indicating the presence of genotype x location interaction on the genetic performance of the hybrids. One hundred-grain weight gave the highest h2B estimates at both locations, Field 2 and Share farm (66.4 and 93.8%, respectively), as well as in the combined analysis (80.2%). Narrow-sense heritability (h2N) estimates obtained from the variance components method were generally in agreement with those from the parent-offspring regression method, although those obtained from the latter were slightly higher for almost all traits. The h2N estimates for grain yield recorded were 54.0 and 36.7%, at field 2 and Share farm, respectively, from variance components method, while 44.7 and 34.2%, respectively, from parent-offspring regression method. Grain yield of the hybrids was most highly correlated with grain weight and grain weight/ear. Grain yield correlations with grain weight gave r values of 0.87, 0.90 and 0.91, respectively at field 2, Share farm and the locations combined, while its correlation coefficients with grain weight/ear were 0.87, 0.81 and 0.90, respectively. Flowering and maturity characters were negatively correlated with most other characters, indicating that early flowering and maturing hybrids were more favourable for grain yield and the other characters measured. Among the yield components themselves, highest correlations were shown between ear weight and grain weight/ear, where r-values recorded were 0.99, 0.96 and 0.98, respectively at field 2, Share farm and the locations combined. Promising hybrids identified in the study could be further utilized in the hybrid maize development programme.