Common root rot caused by Aphanomyces euteiches, is a major soil borne disease of pea in many countries. Genetic resistance is considered to be the main way to control the disease. The role of plant root architecture in Aphanomyces root rot resistance is not well known. This study aimed at identifying pea lines with high levels of resistance in a collection of 175 accessions enriched with sources of resistance and root architectural traits harbored by resistant lines. The collection was assessed for resistance to A. euteiches on the roots and on the aerial plant parts, both in controlled conditions and in a four-year and multi-location field disease network. The collection was also described for root architectural traits on healthy and infested plants in controlled conditions at young plant stage. Lines with higher levels of resistance than partially resistant controls were identified. Susceptible and partially resistant plants mostly showed a decrease of lateral root density and dry weight when compared to healthy controls. However, some resistant lines maintained both root density and dry weight, suggesting their ability to preserve the root system in response to infection. These results will be confirmed in the field using a set of contrasted genotypes. Genome wide association analysis will be performed to compare the genetic control of Aphanomyces root rot resistance and of root architecture traits in response to infection.