In this study the viscoelastic properties of pea and soy protein pastes with concentrations ranging from 10 to 21%w/w were correlated with their ‘printability’ following extrusion 3D printing. The rheological parameters G´, tanδ and σ_y were affected by the protein concentration, and a different viscoelastic behavior was observed for PPI and SPI pastes. At low protein concentrations (10–16%w/w) SPI presents a more elastic behavior than PPI, whereas at higher protein concentrations (>17%w/w) their rheological behavior was similar. No self-supporting structures could be printed for pastes with protein concentrations <15%w/w. In the protein range of 15–17%w/w, SPI formed more stable 3D printed objects compared to PPI. SPI shows a more elastic structure that increases stability against collapse during 3D printing. At higher protein concentrations for PPI, the increase of G´, σ_y and K counteracted the importance of n and tanδ, resulting in self-supporting 3D printed products comparable to SPI. Industrial relevance: This work provides a better understanding of the importance of rheology of plant-protein food inks to printability by attempting to establish printing predictors, which is important for the development of new inks for 3D printed foods.