Growth conditions of AgGaS2 single crystals by a self-seeding vertical gradient freezing method were investigated. It was found that the most effective parameter on the complete seeding was the length of the capillary tube below the neck. Single crystals were grown successfully and reproducibly at a length longer than 70 mm independent of the other growth parameters. Macro-defects like cell structures, were not observed in grown crystals, only lamellar twins and platelet precipitates lying on the {100} planes. Dominant excitonic emissions and weak deep emission intensities in measured photoluminescence spectra confirmed the good quality of grown crystals. © 1998 Elsevier Science B.V. All rights reserved.