Genetic variability of 22 populations of Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae) was studied by comparison of allozyme frequencies at 15 loci. Seven loci were polymorphic at the 99% level. Populations originated from the south of France, Portugal, Morocco, Tunisia, Burkina Faso and Ivory Coast. Few significant deviations from Hardy-Weinberg equilibrium occurred, except for the Acp locus. Overall comparison of allele frequencies revealed significant differences for four loci, although the value of θ was low (0.007). At a lower geographical scale, two situations were observed. Populations from France and Portugal showed significant differences when comparing allele frequencies, although θ was low (0.0099). On the other hand, in northern and western Africa, no significant difference exists even when comparing populations located on either side of the Sahara desert. Results are discussed in relation to the migratory abilities of the species.