The present paper describes the applications of the genetic immune recruitment mechanism (GIRM) which is a combination algorithm of the genetic algorithm (GA) and immune recruitment mechanism (IRM) founded upon the immune network model. The GIRM is applied to the optimum design of a truss structure. Two optimization problems of a ten-member truss structure are examined. The problems are 1 ) to find nodal locations of the truss with minimum weight and 2 )to find combination of materials of truss members with minimum weight and minimum cost under the constraints of full stress and buckling. Simple GA is also applied to the same problems. Comparison of the results by GIRM and simple GA shows the effectiveness of the GIRM.