SQPpro is a piece of software that aims at solving a nonlinear optimization problem with nonlinear equality and inequality constraints. The functions defining the problem must be at least once differentiable. The implemented algorithm uses an SQP approach, which is a workable version of the Newton and quasi-Newton methods. The quadratic optimization that has to be solved at each iteration uses the solver QPAL. The constraint Jacobian matrices can be strored in dense or sparse structures; in addition the Hessian of the Lagrangien can be approximated by the BFGS (dense) or $\ell$-BFGS (sparse) formula. SQPpro is written in Fortran-2003.