Organic nanocrystals have been extensively studied in recent years for their unique optoelectronic properties and for applications in medicine. We report the first synthesis of nanocrystals from the dye compound indigo by reprecipitation. Scanning electron microscopy and dynamic light scattering reveal the particles to be approximately 10-20nm in size, among the smallest organic nanoparticles reported, while powder X-ray diffraction shows similarities to previously reported bulk crystals of indigo. The intense visual absorption peak of the nanoparticles is blue-shifted relative to bulk crystals, consistent with previous observations for nanoscale materials. Potential medical applications are discussed.