This piece of software implements the Spectral Conjugate Gradient method (SCG) for unconstrained optimization introduced in [1]. [1] E. G. Birgin and J. M. Martínez, A spectral conjugate gradient method for unconstrained optimization", Applied Mathematics and Optimization 43, pp. 117-128, 2001. Description of the files: scgma.f : master file and scg subroutine that implements the Spectral Conjugate Gradient method for unconstrained minimization described in E. G. Birgin and J. M. Martinez, "A spectral conjugate gradient method for unconstrained optimization", Applied Mathematics and Optimization 43, pp. 117-128, 2001. For an easy test, download the file scgma.f, compile typing f77 scgma.f -o scgma and execute typing scgma. The output that will appear in the screen will be the application oh SCG to a very easy problem implemented in the subroutines inipoint : which set the initial guess; and calcfg : which computes the objective function and its gradient simultaneously. Both subroutines can be easily modified to solve your own problem.