SummaryTwo fluorescent dyes, sulpho‐rhodamine B and lissamine yellow FF, and three non‐fluorescent dyes, chlorantine fast green, sirius red and Chicago blue are compared for use in the identification of water transmission routes in structured soils. Subsequent to the flow of labelled water, a microsampling and extraction technique is employed to identify dye distribution in relation to structural features. The desirable properties of the dyes tested include stability over a wide pH range, anionic character and high molecular weight, the latter to reduce lateral diffusion from the transmission route. In these aspects they provide suitable alternatives to fluorescein and pyranine used by previous workers. The fluorescent dye lissamine yellow FF was found to be the most suitable for tracing rapidly moving water under field conditions. The transmission routes identified in field soils were associated with structural features readily recognized by routine soil survey techniq