This paper presents the results of a six year field study of wild Avena species and their response to vernalization and photoperiod. The accessions of twenty one wild and weedy species were tested under 12-hr and 18-hr daylength and cold temperatures (for 40 days at +2°C) treatments and without it (as a control). The results demonstrate that for the majority of species evaluated, cold temperature requirements had a greater influence on heading date and the duration of the vegetative period than daylength. Genotypes with neutral, weak and strong reactions to all treatments were found and spring and winter types were selected. The results further demonstrated that daylength-insensitive forms occurred in the south Mediterranean region and adjacent southern territories.