The idea of maximizing the net present value of the cash flows of a project has gained increasing attention over the past decades. Several solution procedures have been presented in the literature to cope with these financial aspects of project management. In this paper we compare three solution procedures for the unconstrained project scheduling problem with discounted cash flows. Each activity of this unconstrained project scheduling problem has a known deterministic cash flow which can be negative, zero or positive. Progress payments and cash outflows occur at the completion of activities. The objective is to schedule the activities subject to the precedence constraints and a fixed deadline in order to maximize the net present value.We compare two recursive search algorithms and a first-order steepest ascent approach for project scheduling problems where both minimal and maximal time-lags between the activities are considered. All procedures exploit the idea that positive cash flows should be scheduled as early as possible while negative cash flows should be scheduled as late as possible within the precedence constraints. The procedures have been coded in Visual C++, version 6.0 under Windows 2000 and have been validated on well-known problem sets.