A large body of research in the measurement of software complexity has been focused on imperative programs, but little effort has been made for logic programs. In this paper, a set of complexity metrics for concurrent logic programs are proposed, which are specifically designed to quantify the information flow in concurrent logic programs. These metrics are defined based on the argument dependence net (ADN) of a concurrent logic program which is an arc-classified digraph to explicitly represent various program dependences between arguments in the program. The proposed metrics can be used to measure the complexity of a concurrent logic program from various different viewpoints.