The aim of the study was to explore the acceptability of 14 species, varieties, and cultivars of grain legumes (Fabales: Fabaceae) to the pea aphid, by investigating the aphid probing behavior using the electrical penetration graph (EPG) technique. Phaseolus coccineus L. 'Felicia', Pisum sativum L. 'Medal', P. sativum arvense (L.) Poir. 'Fidelia' and 'Hubal', and Vicia faba L. 'Dragon' are highly susceptible, with no antixenosis potential against Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae): aphid probing and feeding activities were not impeded. Lathyrus sativus L. 'Derek', Lupinus luteus L.'Perkoz', Vicia faba minor Beck. 'Sonet' are moderately susceptible to A. pisum infestation, with minor antixenosis potential and with antixenosis factors in non-phloem tissues. Aphids on these plants had difficulty to attain the phloem phase and phloem sap ingestion phase. During phloem phase, ingestion lasted for long periods of time. Lens culinaris Medik. 'Green' and Phaseolus vulgaris L. 'Boruta' are moderately susceptible to A. pisum infestation, with minor antixenosis potential and with antixenosis factors in the phloem. Behavior of aphids during pre-phloem phase was similar to that on highly susceptible plants but individual phloem phases and sap ingestion phases were short and contained a high proportion of watery salivation. Glycine max (L.) Merr. 'Aldana', L. angustifolius L. 'Boruta', P. coccineus 'Rothbluende', and P. vulgaris 'Mamut' are highly resistant to A. pisum infestation, with high antixenosis potential and with strong antixenosis factors in non-phloem tissues: aphid probing time was shortened, non-probing intervals between probes were long, and the success rate in reaching phloem phase was very low or none.