The flow injection introduction of samples that would be difficult by conventional nebulisation owing to dissolved solid content, viscosity or quenching effects on flame reactions is demonstrated. The various ways of achieving sample dilution by control of volume injected, tube dimensions and flow-rate are discussed and a manifold described for producing solutions for calibration purposes and diluting off-range samples. The important characteristics of the nebuliser and instrument for flow injection work are evaluated. A simple manifold for investigating interference effects is described and its use illustrated for some well known effects. The possibilities of achieving pre-treatment by solvent extraction and extension to include indirect methods are discussed and the role of flow injection procedures in the method development for, and the extension of the range of application of, flame atomic-absorption spectrometry is critically evaluated.