This paper reports the successful elaboration and study of plasticized starch nano-biocomposites elaborated with needle-shaped nanofillers, namely natural sepiolite (SEP-Na) and sepiolite organo-modified with cationic starch (OSEP-CS). The transmission electronic microscopy has highlighted a well-nanodispersed morphology with almost individual sepiolite needles. It has been shown that different micro/nano-structurations are obtained with the variation of the cationic starch content. Depending on its concentration, it could act as a flocculating agent or a compatibilizer. Finally, uniaxial tensile tests have evidenced the interest in using sepiolite nanofillers to tune the plasticized starch properties, even in comparison with the more common montmorillonite-based nano-biocomposites. Thanks to these needle-shaped nanofillers, the material stiffness is increased without decreasing its properties at break. © 2009 Elsevier Ltd. All rights reserved.