The objective of this study was to explore the production of an expanded snack entirely based on pea- and oat-rich fractions using the extrusion technology. The effect of the die temperature, HZ6 (146–175 °C) and blend moisture content, MC (11.2 and 16.8% dry basis) were investigated aiming at maximizing expansion, while obtaining a good texture and pleasant sensory perception. The best response was obtained with a HZ6 of 160 °C and MC of 11.2%. MC was the parameter that most influenced final extrudate properties/responses. The gross composition of the raw-material was not modified by extrusion processing apart from a decrease in glucose and fructose content attributed to Maillard reactions. The snacks contained 3.5 g of β-glucan per portion. This is high enough for both approved EFSA health claims: lowers cholesterol and reduces post-prandial glucose response. Display omitted •Successful production of expanded extrudates based on pea- and oat-fractions.•Blend moisture content had the greatest impact of extrudate properties.•Higher porosity and brownish color were obtained for highly expanded extrudates.•Sensory attributes highly correlated with those determined by texture analysis.•β-glucan molecular weight slightly reduced at highest Specific Mechanical Energy.