Morphological, pathological and possible genetic variations among forty two Cephalosporium maydis isolates, obtained from 13 Egyptian Governorates, were evaluated. Clear differences among C. maydis cultures grown on PDA+0.2% yeast extract (PDAY) were found with respect to their growth rate and sporulation. However, the majority of isolates grew at the normal growth rate (7 days after incubation at 27±2°C), showed whitish grey and white colour, had rhizoid margin and displayed intermediate growth density. In most isolates, the maximum number of spores was observed at the third day of incubation at 27±2°C, but no spores were produced after the sixth day of growth. Under greenhouse conditions, the virulence of C. maydis isolates against maize cv. Boushy revealed that, in general, all the tested isolates were pathogenic and differed in their aggressiveness. Some isolates showed the onset late wilt symptoms, 65 days after sowing, whereas symptoms started to appear, 75 and/or 95 days after sowing. However, isolate No. 9 from Gharbiya caused the highest infection, 95 days after sowing (93.3%); meanwhile isolate No. 48 from Wadi El-Natroon recorded the least infection (13.3%). A highly negative correlation was observed between infection percentages and each of plant height or dry weight of plants. Also, no correlation was observed between morphological and pathological characters of the tested isolates. Genetic variability among 14 C. maydis isolates was also carried out in the present study using RAPD-PCR technique. Different levels of genetic variability were recorded among the tested isolates and the reference ones, where they clustered into four phylogenetic lineages. Moreover, slight relationship between the lineage of isolates and any of their geographic origin and their virulence was observed. However, no correlation was noticed between the lineage and the morphological characters of the tested isolates.