In this paper, a rational approach for multi-objective design and optimization of parabolic trough solar collectors for different design environments is presented. A macro and micro-level partitioning of the design problem is implemented. In this process, environmental goals, objectives, and limitations are accounted for at the macro-level of design. At the micro-level of design, subsystem designs that were developed at the macro-level design are integrated such as to maximize the collector all-day thermal efficiency. A seven-step procedure is developed to optimize the collector dimensions at the micro-level of design. The process is demonstrated through illustrative examples.