The paper deals with an application of the artificial immune system (AIS) and the particle swarm optimizer (PSO) to the optimization of composites with thin rigid fibers. The boundary value problem is solved using the boundary element method (BEM). The numerical examples demonstrate the optimization of the distribution and orientation of fibers in a composite. The objective functions depend on effective elastic properties. Two separate independent optimization methods are used to confirm the correctness of the obtained results (AIS and PSO). The bioinspired approach shows that the method based on the artificial immune system or particle swarm optimizer is an efficient technique for solving computer-aided optimal design problems (maximalization of the Young’s modulus or Poisson’s ratio) and allows for the development of new materials.