A number of fluorescent dextrans were screened for axonal transport properties within the rat CNS. One compound, Fluoro-Ruby (FR), was found to be particularly sensitive for demonstrating retrograde and particularly anterograde axonal transport. The tracer may be either pressure or iontophoretically injected, and the fixed tissue can be examined without histochemical processing. The technique can be combined with a wide variety of other neuroanatomical methods.