In the present work, an extensive analysis is developed for an evaluation of the thermal performance of a solar-powered H2O/LiBr absorption cooling system using a step-fin flat-plate collector (SFC). The performance parameters, namely, collector efficiency factor, heat removal factor, and collector efficiency, for the SFC is derived. A system simulation model has been developed to analyze the system performance-that is, to identify an operating criterion as a function of the collector fluid inlet temperature (T-FI). It has been observed from the results that the performance of the system depends strongly on T-FI. Simulation results show that the system operates optimally ( maximum coefficient of performance) at an optimal T-FI. When the system runs at this optimal value of T-FI, minimum collector material is required. Thus, when using SFC in place of a rectangular-fin flat-collector, thirty-five percent or more collector material can be saved. However, it has been observed that the effect of thermal conductivity on the plate volume of SFC has a marginal effect.