We compared the antigenicity of p126 Plasmodium falciparum peptides with predicted antigenic regions identified using the methods described by Garnier et al. (1978) and Chou & Fasman (1974). For this purpose nine different P. falciparum peptides were synthesized in accordance with the deduced amino acid sequence of the p126 gene, and their reactivity was tested using an enzyme linked immunosorbent assay against sera from individuals with a natural malaria infection. Both predictive methods gave similar antigenic-index scores, however, a comparison of these predictive results with data obtained by ELISA showed that the probability of a correct prediction was only around 45% for both cases. Thus, in our view computer software could not be used in isolation for screening purposes, and other parameters must also be taken into account when using such software to assess antigenicity.