The rheological properties of wheat meal and wheat starch with and without added wheat germ oil (WGO) and of oat flour under low moisture conditions were investigated using a capillary rheometer and the flow behaviour described by the power law model. The consistency coefficient of wheat starch and wheat meal decreased with increase in moisture content from 21% to 28% (wet weight basis) and barrel temperature from 100 degrees C to 125 degrees C and with the addition of WGO to 8%. The flow behaviour index of wheat starch and wheat meal generally increased with this increase in extrusion moisture content and temperature and with the addition of WGO. Wheat starch showed the highest consistency coefficient and oat flour showed the lowest under identical set extrusion conditions of these temperatures and moistures. Both power law indices for oat flour showed a less well defined change for the same range of moisture and temperature. The effect of WGO addition to wheat starch or meal to the 8% level was to reduce their viscosities towards the value observed for oat flour. The power law indices varied with die diameter indicating possible wall slip.