Organic passion fruit fiber is obtained from organic passion fruit rind and is an interesting source of dietary fiber with potential for use in food products such as breakfast cereals. However, various researchers have confirmed the presence of cyanogenic compounds in passion fruit. The objective of this study was to evaluate the effect of the thermoplastic extrusion process on the residual quantity of total cyanogenic compounds (TCC) in extruded organic breakfast cereal produced with corn flour and different levels of passion fruit fiber added to the formulation. For the production of the extrudates, a 2 3 complete factorial design was followed, that permitted the analysis of the results by response surface methodology. The effects of the quantity of passion fruit fiber (0-30%), feed moisture content (18-28%) and barrel temperature (120-160°C) on the residual quantity of TCC were studied. The raw passion fruit fiber presented 748.3 mg/kg of TCC. The extruded products presented TCC contents of 0-254.1 mg/kg, increasing significantly with the increase of the quantity of passion fruit fiber. The residual quantity of TCC was influenced by feed moisture, while temperature had no significant effect on this response. Nevertheless, only a small reduction of cyanogenic compounds was verified in the breakfast cereals produced by thermoplastic extrusion. Thus, it was concluded that the toxicity of the cereal blends was not improved by the extrusion process.