Sabinin Algebras and Nonassociative Lie Theory Ivan Shestakov Abstract: Lie algebras naturally apear from and are related with various associative objects: associative algebras, Lie groups, Hopf algebras, groups with central series, etc. There were many attempts to extend some of these concepts and results to nonassociative setting. We show that the so called hyperalgebras or Sabinin algebras provide a good substitution for Lie algebras in what might be called a "nonassociative Lie Theory": the Lie correspondence between loops and Sabinin algebras, the nonassociative Poincare-Birkhoff-Witt theorem, the Milnor-Moore Theorem for nonassociative Hopf algebras, the Magnus imbedding for loops with central series give an evidence to this assertion.