This paper reviews the principal strategies for multicomponent determinations of pharmaceutical products and related compounds using flow-injection analysis (FIA). The relevancy of this topic in the pharmaceutical field and close areas such as clinical, food and biochemical analysis is pointed out. As an alternative to chromatographic and electrophoretic methods, multicomponent FIA is specially suitable for a rapid quantification of analytes and processing large sets of samples. The achievement of selective measurement conditions to carry out the quantification of each drug without interferences is commonly needed in multicomponent analysis. The main approaches for gaining selectivity are based on specific reagents, multi-way or fast-scanning detectors, serial and parallel multi-channel manifolds. Alternatively, chemometric methods for data analysis can be used when selectivity is not fully accomplished.