The study aimed to determine the infestation level of the cereal cyst nematode Heterodera avenea (Wollenweber, 1924) in the Chlef area. Nematological analysis, considered the most reliable diagnostic method, was carried out as it enables both identification and quantitative estimation of the nematode populations in the soil. H. avenae detection surveys were conducted in six cereal growing areas of the Chlef region. The sampling conducted in the 18 cereal plots based on two depths of the ground, 0 to 10 cm and 10 to 30 cm. The results revealed that 8 to 21% and 8 to 30% of the plots surveyed were infested. The infestation rate varies between plots in the same region according to the number of eggs, the estimated second larval stage per gram of soil, and rooting depth. Variance Analysis (ANOVA) showed that the infection rates at the two depths were the same. This is most likely a result of the type of tillage that most cereal producers use, which is essentially repetitive superficial disking in plots to prepare the soil, which leaves cyst concentrations at the same depth of 0 to 30 cm.