In order to study the plant response to parasitic plants and the molecular basis of the resistance we have used a proteomic approach. The root proteome of two accessions of the model legume <em> Medicago truncatula </em> and crop pea displaying differences in their resistance phenotype, in control as well as in infected plants have been compared. We report quantitative as well as qualitative differences in the two-dimensional gel electrophoresis (2-DE) maps between plant genotypes and treatments (control, non-infected, and infected). Differential spots spots were successfully identified by peptide mass fingerprinting (PMF) following MALDI-TOF mass spectrometry. Many of the proteins identified found showing significant differences between genotypes and after parasitic infection belong to the functional category of photosynthesis and energetic metabolism, and defence and stress-related proteins. Data will be presented and discussed in terms of plant spp. and genotype common and differential responses, as well as compared with those previously obtained by using classical biochemical and transcriptomic approaches. Data have been published or submitted (Castillejo et al., 2004. Phytochemistry 65: 1817; Jorrin et al., 2006. Euphytica 147: 37; Rossignol et al., 2006. Proteomics 6: 5529; Rispail et al., 2007. New Phytologist 173: 703; Castillejo et al., 2007. Plant Physiology (submitted).